Inside an Illinois restaurant, tables full of diners filled up on breakfast. No one knew a killer sat among them, drinking hot tea and delivering a cold and callous confession of murder.

It's the Deerfield, Illinois story of a star NFL player, the women who loved him, and a gruesome murder.

Rhoni Reuter had never been happier. Rhoni was expecting her first child with her boyfriend, former Chicago Bear Super Bowl champion Shaun Gayle. The couple had even come up with a name for their little girl: Skylar Gayle.

She was 7 months pregnant, just over 40 days from bringing a life into the world, when Rhoni Reuter's life was taken.

The legendary tough guy Shaun Gayle sobs hysterically when he finds out the love of his life is dead, and the motive for Rhoni's murder was Baby Skylar.

They were football royalty in Deerfield, Illinois: Shaun Gayle, the much-adored Chicago Bear, and Rhoni Reuter, the stunning brunette working her way up in the fashion field.

Retired Lake County, Illinois Major Crimes Task Force Detective George Filenko says the two met at a Bears training camp near Rhoni's hometown in Wisconsin.

For nearly two decades, Rhoni and Shaun were blissfully inseparable, traveling the globe. Then news that blindsides the couple: at 41, Rhoni discovers she's pregnant.

"She was very excited," said Illinois Assistant State's Attorney Ari Fisz.

The older mom takes every safety precaution. She even wears a pearl medic-alert bracelet. That way if anything ever happens to her doctors will know to save Baby Skylar.

Initially the football star doesn't seem as thrilled about becoming a dad. But over time, state's attorney Ari Fisz says, Shaun tells friends he's warmed up to the idea.

On the morning of October 4, 2007, just a little more than a month away from delivering her miracle baby, Rhoni Reuter heads off to work. But when she opens her front door, a nightmare is there to greet her with a loaded gun.

Rhoni's neighbor calls 911 and tells the operator she heard seven to eight shots, followed by a loud thud. And she told detectives the shots sounded strangely muffled.

"She had recently seen a movie where there was a gun that was fired using a silencer, and she said that that's what it sounded like," said Ari Fisz.

When Deerfield Police arrive, they find the expectant mother dead on the kitchen floor with a sonogram hanging over her head on the refrigerator.

"The police and paramedics responded right away, but it was very obvious there was nothing they could do for Rhoni or her child," said Fisz.

"This was targeted," said George Filenko. "No way did we ever suspect that this was random."

Deerfield Police assume Rhoni Reuter was the target, until they get a closer look.

"The first shot appeared to be targeted right at her stomach," said Filenko.

Police say during Rhoni's last breaths, she cradled her unborn baby girl, trying to protect Sklylar from the hail of bullets. But she couldn't save the baby, and the final bullet ensured Rhoni wouldn't survive either.

"The final wound sort of was a coup de grace, very cold-blooded, was a shot to the head, to the back of the head, almost like an assassination-type thing, a final ending," said Filenko. "We didn't know what the motive was."

Cops say there was no forced entry into her apartment, or fingerprints, just some unspent 9mm shell casings scattered haphazardly around Rhoni's body.

"Normally in a case like that, the gun's jamming for some reason," said Filenko.

Police track down a neighbor who reports seeing a dark-skinned male running from the scene.

"One of the witnesses indicated that the person that they saw walking away was short, thin African-American-looking person in appearance, with dark curly hair," said Fisz.

Another witness told cops they remember a black car speeding away.

News of a possible killer on the loose rocks the city of Deerfield.

"Nothing bad ever happens in Deerfield, so word of the shooting spread quickly," said Ari Fisz.

Across town, Shaun Gayle gets a call from a local reporter, telling him a pregnant woman has been shot in Rhoni Reuter's neighborhood.

His fears are confirmed when he calls police and finds out Rhoni is dead.

"He was very upset on the phone," said George Filenko. "You could barely make out what he was saying."

While many rushed to console the grieving gridiron great, Deerfield Police weren't buying his tears.

"Initially, Shaun was considered a person of interest, almost immediately," said Filenko.

Shaun tells police he had nothing to do with Rhoni's murder. He had an alibi.

"He was getting his hair cut in North Chicago," said Fisz.

Was there a possibility he could've committed the crime and then gotten back to the barber shop in that time frame?

"It was theoretically possible," said Fisz.

So he wasn't ruled out because of that alibi.

"Not because of the alibi, no," said Fisz.

But what about that eyewitness's description of the slim, African-American man spotted fleeing the scene?

"[Shaun Gayle] is a former professional football player, and so he was a bigger guy, and the physical build didn't match at all," said Fisz.

Still, cops couldn't rule out the possibility Shaun had an accomplice, or hired a hitman.

"Unfortunately, suspect number one is going to be the other half," said George Filenko.

The big question cops couldn't answer: Why would Shaun Gayle want to kill Rhoni Reuter and his unborn baby girl?

Investigators stumbled across a bizarre letter inside Rhoni's purse, written in broken English.

"It was a letter drafted to a number of women, I believe there may have been 15, 16, 17 women on this letter, including Rhoni," said Filenko.

Cops soon discover the women on the list had one thing in common: they were all sleeping with Shaun Gayle.

Cops in Deerfield, Illinois are starring at a possible motive for Rhoni Reuter's murder: 17 of them, in fact, all in a bizarre letter found near Rhoni's pregnant bullet-riddled body.

The letter, written in broken English, lists the names of 17 women and their phone numbers. All of them girlfriends or lovers of the father of Rhoni's baby, former Chicago Bear Shaun Gayle.

"It basically was very blunt: 'He's having relationships with all these women, he's out there playing all of you,'" said retired Lake County, Illinois Major Crimes Detective George Filenko.

While Rhoni and Shaun appeared to be the picture-perfect couple, detective George Filenko quickly learned their private life was complicated, and extremely crowded.

"I believe the best way to describe it was an open relationship, on Shaun's part," said Filenko.

When cops question Shaun about the letter, he says Rhoni knew he was seeing other women. But detectives were hearing a very different story.

"From the indications we got from some of Rhoni's friends, she wasn't exactly 100-percent bought into that," said Filenko. "They were all ongoing."

At first cops wonder if Rhoni confronted Shaun about the other women, and he snapped, or if one of the 17 players on Shaun's sex team didn't want a baby to take the football great out of the game.

As cops were zeroing-in on Shaun Gayle as their prime suspect, something unexpected happened: Shaun handed the Deerfield Police his own number one suspect.

"One of the first people that he mentioned to the police as a possible suspect was Monika Kurowska," said Assistant Illinois State's Attorney Ari Fisz.

Monika Kurowska, a beautiful fitness model and personal trainer, who happened to be the first name on the list. Shaun had been seeing the Polish bombshell for a few years. But their relationship had recently ended badly -- very badly.

"Apparently Monika thought that the relationship was monogamous. She turns up at Shaun's house unexpected one evening, walks up to Shaun's house, looks through the window and sees Shaun with another woman," said Filenko.

Shaun says Monika became violent, busted out a window at his home and then began leaving threatening phone messages. He even suspected Monika had somehow hacked into his email account.

"It finally got to the point where he felt that she was stalking him," said Filenko

The tough football player was so terrified that just days before Rhoni was murdered, he had filed a restraining order against Monika Kurowska. Shaun tells cops he also believes Monika, a Polish immigrant, is the one who wrote the letters.

"There was broken English in the way that the letters were written, and Monika was from Poland and spoke in broken English," said Ari Fisz.

But Monika denies sending the letters and tells police she was with a client at the exact time Rhoni and her unborn baby were gunned down.

"She could not have done it," said Fisz.

All eyes shift back to Shaun Gayle. Three weeks after Rhoni's vicious murder, cops seize Shaun's computer and find something that sets off warning bells: Shaun had a cyber-stalker. Someone had "ghosted" his hard drive and had been controlling his computer remotely, tracking the former football great's every move -- and they'd been doing it for nearly two years.

"Emails, names, addresses, personal information like that, so access to everything," said Filenko.

Cops say it certainly wasn't Monika Kurowska. So then who?

Detectives go back to that lineup of the 17 women. And then a retired cop blows the whistle on one of them.

"They said 'If anybody's done this, it's Marni Yang," said Filenko.

Turns out Marni Yang is number 15 on that list from Rhoni's purse.

"Two things drove her: getting attention and sex," said photographer Len Dorman.

One by one, police in Deerfield, Illinois have been checking off the 17 names on that bizarre letter found at the murder scene in Rhoni Reuter's purse. Then detectives hit number 15. Marni Yang was one of several women sleeping with Rhoni's longtime love Shaun Gayle.

But Shaun wasn't Marni Yang's only lover either. One Chicago cop who had sex with Marni Yang told detectives they should pay a lot of attention her while investigating Rhoni's murder.

"He had had a relationship with her and he had broken it off. It didn't go well," said retired detective George Filenko. "Marni threatened him, threatened his family."

The officer says she even tried to blackmail him when he threatened to break up with her.

"He was worried enough to -- he was close enough to retirement to put in his papers and move his entire family out of town and out of sight," said Filenko. "They moved out of state."

Cops were intrigued. Now they want to know all they can about Marni Yang.

"She was loose, a little bit wild, especially for her age," said photographer Len Dorman. "Two things drove her: getting attention and sex."

Yang, a mother of three, dabbled in real estate, had a side gig as a fitness model, and a secret reputation as a man-eater.

"I've seen this kind of behavior before. Usually in a stripper or somebody husband-shopping," said Dorman.

Len Dorman was Marni Yang's photographer and friend.

"She kind of conned [Shaun Gayle] into being somebody who was going to work real estate for him. I got the idea that you had basically 'a player meeting a player' here," said Dorman.

Dorman says Yang bragged about her relationship with Shaun, but he says Marni was obsessed with dating cops, and often showed up at the station to study how they investigated crimes.

"She has had lessons from other Chicago police officers on how to shoot a gun and how to cover up a crime," said Dorman.

Searching for clues, Deerfield Police detectives head to Marni Yang's condo and dive head-first into her garbage.

"This is very, very fundamental police work, is 'Dumpster-diving.' Once somebody, by law, pushes their garbage out onto the public easeway, it's open game," said George Filenko.

"They would drive over there, they would empty her trash cans into a van, drive away, bring it back to the police department and look through her trash," said Ari Fisz.

And in the trash, they found what they think is a treasure trove of evidence.

"As luck would have it, they recovered some receipts that were extremely interesting," said Filenko.

The first receipt is to a very specific online book store.

"We tracked the order and it was for a book on how to build silencers," said Filenko. "Then there was another receipt from a local Home Depot and that receipt actually listed out the items. We looked through the books, the items in most of the homemade silencers fit the items on the Home Depot receipt," said Filenko. "We verified that it was her making that purchase through video. Additionally we saw her purchasing a bucket and quick-drying cement."

Detectives haul Marni Yang in for questioning.

Detective: "Did you purchase this book?"

Marni Yang: "Yes I did."

Detective: "Why did you purchase the book on how to make disposable silencers?"

Yang: "It was a joke."

Marni Yang claims the book was a gag gift for a cop she was dating. But how would she explain buying all the materials needed to build a silencer?

Detective: "Did you ever put anything like this together or buy anything?"

Yang: "As far as to build one of those? No, but it gave me a really good idea for a science project."

Detective: "You tell us it was a gag and that you then purchased items from the book matching up to try to see if you could make one of these things for a science project?"

Yang: "Right."

But what about that bucket and bag of concrete she's seen buying on a store surveillance camera?

Detective: "Is there a reason on October the 5th, the day after Rhoni's brutal murder that you're at Home Depot buying a 5- to 10-gallon bucket and concrete mix?"

Yang: "Well, yeah, it was for the tile in the basement."

Detective: "When did you work on your basement?"

Yang: "I ended up not working on my basement."

"We thought there was something there that just didn't click," said George Filenko.

But Marni Yang also has an alibi.

Yang: "I had car trouble as soon as I got home."

"Home," said Filenko. "She said that the battery was dead so she had called a friend of hers who was a Cook County bailiff, a court officer who was constantly there to help her."

Marni Yang claims without a car she was stuck at home at the exact time Rhoni Reuter was murdered. But before she leaves, she tells detectives she believes someone may actually be stalking her.

Yang: "It was kind of strange because I had seen a car drive around my block three times kind of slow."

Detective: "You're talking about the block where you live?"

Yang: "Yeah. Then I am out and then and I see it come around again twice, like, and then it came around three times."

Detective: "Did you see the person in the car?"

Yang: "No, I remember that the sun was out so it was like reflecting off the, reflecting off the windows, so I couldn't see."

At this point Deerfield Police are officially stumped. Then a possible break: Police locate surveillance images of a dark-colored car leaving the scene of the murder. That black Volkswagen leads police to a car rental company.

"He told me that he almost fell off his chair when the rental history popped up," said Ari Fisz.

Deerfield, Illinois Police believe the person behind the wheel of that black Volkswagen unloaded a 9mm semiautomatic Beretta into Rhoni Reuter, killing Rhoni's and Shaun Gayle's unborn baby girl Skylar.

The car caught on surveillance cameras doesn't match Shaun Gayle's vehicle or any of the 17 current or former lovers of the football player. But a detective working the case has a hunch.

"He sat down and opened up a beer and just started putting relational names into this database," said George Filenko.

Then he checks to see if any of them had rented a car recently. He strikes gold.

"He told me that he almost fell off his chair when the rental history popped up and he saw that Marni Yang herself rented a vehicle," said Ari Fisz.

A local rental company confirms Marni Yang rented a black Volkswagen the day before Rhoni Reuter was gunned down. It was just like the one featured in surveillance images caught leaving the scene of the murder.

And the rental agent remembers Yang was very selective about the car she wanted.

"The first vehicle she got was a very descriptive vehicle, it had this really wild blue color to it, she brought it right back and said 'I want a dark-colored vehicle that's very plain-looking,'" said Filenko.

But here's the strange part: the rental company says they didn't deliver the car to Yang's address.

"The address that she used was Christi Paschen's address," said George Filenko.

"Christi Paschen was Marni Yang's best friend," said Ari Fisz.

Adding to the cops' suspicion was the mileage when Yang returned the rental car.

"There were 40 miles that were on the vehicle that Marni had rented and returned," said Fisz. "When the police measured the distance from the rental car place to Christi Paschen's home, and then from Christi Paschen's home to the Deerfield home of the victim Rhoni Reuter, and then back to Christi Paschen's home and back to the rental car company, it was exactly 40 miles."

Then detectives discover MarniYang had a twisted obsession with Shaun Gayle. She was the one who had been cyber-stalking the football champ for the past two years.

How did Marni gain access to Shaun's email account?

"Our theory is that while she was over at Shaun's house, that she 'ghosted,' or copied the hard drive of the computer," said Filenko.

And the night before Rhoni and her unborn baby were killed, Marni Yang and Shaun Gayle had a wild night of sex.

Was she in love with Shaun Gayle?

"I don't know if she was in love with Shaun or not. It certainly seems like she was obsessed with him," said Fisz.

Yang was so fixated, detectives claim she had paid for detailed background checks on the other women in Shaun's life.

"Emails, names, addresses, personal information like that, so she had access to everything," said Filenko.

And she tracked one woman's home address -- that woman: Rhoni Reuter.

"It doesn't take a a seasoned detective to figure out that this just isn't fitting," said Filenko.

Now cops have some tough questions, for the woman who seems to have an answer for everything.

Detective: "Did you check all the girls on the list?"

Marni Yang: "Probably, probably most of them."

Detective: "Did you ever attempt to contact those people as far as in an effort to find out anything about them? Or what their relationship was with Shaun, or anything else?"

Yang: "Oh, I might dial the number just to see if I could get a feeling from the person's voicemail, if, you know, if it's business or not."

Detective: "Was there ever any conflicts between you and Rhoni?"

Yang: "I never met her. I never met her, I never spoke to her. I never."

Yang, a mother of three, says she wanted to make sure Shaun wasn't dating any "wackos."

Yang: "If I'm gonna be involved with you on any level and you're gonna be coming in contact with my kids, better believe that I wanna know and I want to understand everybody else that's associated with you."

Police had also been tipped off by one of Yang's cop boyfriends she's a gun enthusiast.

Detective: "So do you own a firearm now?"

Yang: "Yes."

Detective: "OK, what kind of firearm?"

Yang: "Um, I have, um, four of them actually."

Yang admits she had a 9mm Beretta, the same caliber used to kill Rhoni and her unborn baby. But Yang tells cops it had recently been stolen from her condo.

Detective: "Did you make a police report with Chicago, CPD?"

Yang: "I did not make a police report because I had no homeowners insurance at the time, so I said to myself, nothing is reimbursed for this stuff anyways."

What about that black rental car she rented and had delivered to her best friend Christi Paschen? Simple, Yang tells cops: Paschen didn't have a credit card, and she was just helping her out. But Christi Paschen doesn't sound very appreciative on a secretly recorded phone call with Marni Yang.

"They looked at me and they went 'So why was a rental car delivered to your address and that was seen around the crime scene?'" Paschen says on the recorded call.

Cops find out Christi Paschen is a telemarketer and tap into her phone line. Now their ears are burning.

"I don't [----] remember where the hell I was, Marni," Paschen says.

"Wait, what are you talking about? When?" says Yang.

"The night of the, the night before that stupid murder," says Paschen.

Police believe Marni Yang is the one who gunned down the pregnant girlfriend of former NFL star Shaun Gayle, but they just couldn't prove it. So investigators hatched an undercover operation at, of all places, a Denny's.

Marni Yang is trying to calm down her best friend Christi Paschen, but cops have called Paschen, and she's freaked out.

"Well yes I'm flipping out," says Paschen on a recorded call with Yang. "I've been [----] flipping out all [----] week."

Ever since cops first contacted Paschen to find out what she knows about the murder of Rhoni Reuter. Now they want her to come down to the station.

"I'm in too much [----] as it stands. I've got to go," says Paschen.

"I don't think it's a good idea," says Yang.

Cops suspect Yang is behind the murder of Rhoni Reuter and her unborn baby. The motive? She wanted Rhoni's longtime love, former football great Shaun Gayle, for herself.

Now Yang is trying to coach Paschen to stick to the game plan.

"I think I remember everything," says Paschen.

"They are going to come up with all kinds of phony [----]," says Yang. "Fine."

"Whatever. I'm just going to go over and get this the [----] over with," says Paschen."

It's as if she was trying to assure Christi Paschen that she'd done a good job.

"'You have nothing to worry about, I've got all the ends covered, there's no way that these bumbling idiots are going to find out what actually happened,'" said Filenko.

After Paschen is grilled by detectives, she calls back. This time she's the calm one.

"I mean, I went over everything with them I could remember, but they were like on and on and on about the car," Paschen tells Yang.

Paschen tells Yang she thinks she actually shook cops off their tail.

"I told them I didn't know what they were talking about. I have no fricking clue. So finally they just let me go," says Paschen.

But now Christi Paschen's got a secret. She's spilled her guts to investigators.

"I think even Christi began to understand that she was either going to be a great witness or possibly a co-conspirator," said George Filenko. "Christi said that Marni had been talking about getting rid of Rhoni for quite some time."

"She told the police that she tried to talk Marni out of doing it and Marni told her that if she did commit the murder, she would call Christi at work the next morning and ask her to dinner. That was the code that they used," said Ari Fisz.

The next morning Christi Paschen got this call:

Paschen: "Christi Paschen, how can I help you?"

Yang: "Do you want to go to dinner?"

Paschen: "OK."

During the interrogation Paschen tells detectives Yang was obsessed with the football star. And when she found out Shaun Gayle's girlfriend Rhoni was pregnant, Yang spiraled into a jealous rage, fearing the baby would sideline her relationship.

"We believe that that was the moment that she decided to kill Rhoni, and she put a very carefully executed plan in place," said Fisz.

Yang put her evil plan in motion on the morning of October 4, 2007. She covered her face with dark makeup and her long hair with an afro wig. Then Yang attached her homemade silencer to her 9mm Beretta. She drove over to Rhoni's condo in the black rental car and opened fire.

"This was the most premeditated and carefully executed crime I've ever seen," said Ari Fisz.

Christi Paschen confesses after the murder she drove Yang all around town to dump the evidence. At one point, Yang told Paschen to pull over and stop behind a banquet hall.

"Marni got out of the car, opened the trunk, took out a little sort of handheld shovel, had something in her other hand, walked away from the vehicle and buried something in the ground," said Ari Fisz.

Now, more than a year after Rhoni's murder, Paschen leads police back to that spot.

"Our evidence technicians came out with a metal detector, I think we were expecting to find a gun, they dig this up and they find this bracelet," said George Filenko.

It's that medic-alert pregnancy bracelet Rhoni never took off.

"That was a huge discovery, 'cause now we've got physical evidence linking Marni to the crime scene," said Filenko. "We didn't have the weapon, we didn't have a confession. Everything we had was circumstantial. We needed the one thing that was going to be slam dunk."

To save her own skin, Christi Paschen agrees to go undercover for the Lake County Major Crimes Task Force.

"Christi agreed to wear a body wire and have a conversation with Marni and record the conversation," said Fisz.

They set up a meeting at a Denny's restaurant, and cops were listening in as Marni Yang dishes her own dirt. But as Paschen is walking in, disaster strikes. Her wire comes undone. She tucks in the wire, but she knows Yang is savvy, and if she's suspicious, she won't talk.

Paschen: "So of course I am going to finally ask the question I [----] told you I never ever wanted to know."

Yang: "What?"

Paschen: "When you hid the gun, did you hide it real well?"

Yang: "It's gone."

Marni Yang tells Christi Paschen she buried the gun in a bucket of cement, threw it in a Dumpster.

Yang: "It's under tons and tons and tons of Chicago trash. It's gone."

Paschen's in the clear. Yang never suspects her best friend just served her up to the cops.

Paschen: "Gentlemen, I sure the hell hope you heard."

But without the gun cops still don't have what they need to nail Marni Yang for first-degree murder.

Detectives ask Paschen to meet Yang one more time at that Denny's. And this time Yang cooks her own goose.

Paschen: "I really did not believe you would do it."

Yang: "I didn't believe I would either."

"It's very sad," said Ari Fisz. "She talks about how she waited outside of Rhoni's apartment. And she hid behind the alcove waiting to hear the sound of the door opening and Rhoni leaving."

Paschen: "What did you see?"

Yang: "It was so dark I wasn't even positive that I was making straight shots. OK? And she started screaming, I took the first shot."

"Then she starts describing, 'I emptied a clip into her,'" said Filenko.

Yang: "And then when she went down, she took her foot and she took one good kick at me and got me in the shin. I just took one last shot and finished her off."

Marni Yang was sentenced to life in prison. She will never step foot out of prison.

Crime Watch Daily reached out to Shaun Gayle for comment, but he did not want to talk. But just after Marni Yang's sentencing the football hero said he is now forever haunted by guilt.

"If I had given the dating relationship that she wanted, this tragedy may not have happened," Shaun Gayle told reporters.

Instead of celebrating the birth of little Skylar, Rhoni Reuter's family buried them in a single casket, Rhoni eternally cradling her unborn baby in her arms.

Yang's attorneys asked for a new trial, saying the confession she gave at that restaurant was recorded illegally. They also argued that Yang was denied the opportunity to get a haircut or wear makeup during the trial, which made her appear guilty in the eyes of the jurors. That appeal was been denied. She will spend the rest her life locked up without the possibility of parole.