A successful executive goes off the grid. Her distraught husband is at a loss. The family's beautiful teen nanny in the middle. Then the most gruesome discovery of all.

Tara Grant was a beautiful and smart small town girl with big city dreams.

"In the corporate world she kept moving up the ladder," said journalist and author Andrea Billups, who wrote A Slaying in the Suburbs: The Tara Grant Murder. "She was a perfectionist."

But according to some, that perfectionist married her opposite: Odd and awkward Stephen Grant.

"He was the guy that you thought would grow up and rob a liquor store and leave his name tag on and you'd see him on the 'Stupidest Criminals,'" said Ken McCauley, a childhood friend of Grant's. "Steve wasn't the most popular kid in the world. He wasn't the best-looking. So I guess when I saw his wife I was like 'Wow! Good job, Steve. I never thought you would get someone like Tara.'"

Snagging Tara was a real coup for Stephen.

"Tara's success allowed them to have a very successful life," said Billups. "They lived in a really nice neighborhood, they drove new cars, their children attended a private school."

But with those successes came some sacrifices.

"Tara was working in San Juan and working Monday through Friday, she would jump on a jet Friday afternoon and go back to Detroit and spend the weekend, and then boom, back on the plane on Monday to her work life," said Billups.

While Tara was excelling at her job in sun-soaked San Juan, Puerto Rico, Stephen, who had dreamed of working in politics, was holding down the fort at home as a soccer coach and self-proclaimed "Mr. Mom" to their two small children.

"Stephen Grant loved taking care of his children. He was extremely present in their day to day lives," said Billups.

They seemed to be making it work. But were they really?

"Their public face of this couple seemed a lot more normal than what might have been simmering inside those doors," said Billups.

What was simmering was heading towards a rapid boil, and it was Stephen's growing resentment that was fanning the flames.

"I think that on some level her ascension and his flat line, being, you know, left there with the kids, I think he felt a little bit emasculated by that," said Billups.

So they fought, and Stephen sought the attention of another woman.

"Steve had a girlfriend before he met Tara. They had reconnected," said Billups.

"He was looking for someone to make him feel wanted."

Maybe several someones. It seemed like he was also taking a fancy to the family's beautiful 18-year-old nanny Verena.

"The Grants had employed a German au pair who lived in their home to take care of their children. Stephen began to talk to her because she was the only person in the home with him while Tara was working," said Billups. "Then their conversations turned sexual. He told her bluntly that he would like to sleep with her."

Was it just flirting or did things become physical? Reportedly, a very jealous Stephen suspected Tara had someone on the side herself.

"He found some things on her computer about a previous relationship and it looked like this relationship had been rekindled," said Billups.

And he believed an affair with her boss was making Tara's weekly island getaways less work, more pleasure. Regardless of their actual or perceived dalliances, at least for the time being, they were staying together.

Until one night when that all went to hell.

It was freezing on the Friday night of February 9, 2007 when Tara arrives home from Puerto Rico and informs Stephen she's going back on Sunday, one day early.

"They immediately began to argue," said author Andrea Billups. "He had told her 'This has to stop, you're gone all the time.'"

Reportedly an angry Tara Grant packs her bags and walks out the front door.

"She went down the driveway and got into like a car service, a black-car service, and left," said Billups.

So Tara leaves. Hours later Stephen calls her and leaves voicemail messages. Over the next few days, Stephen calls Tara several times, but gets no answer. He also calls her boss in Puerto Rico and her family, but they aren't worried yet, saying:

"'She's probably just cooling her jets and she's just staying away from you because she's angry, you'll hear from her soon enough,'" said Billups.

But after five days of desperately trying to find her, on Valentine's Day, Stephen reports Tara missing.

"He came in, one of our deputies took a report from him and it was immediately turned over to our detective bureau because it really wasn't adding up," said Macomb County Sheriff's Detective Sergeant Pam McLean.

The intense search is on.

"It was a big deal because, frankly, attractive, well-educated executives didn't go missing in the Detroit suburbs," said Andrea Billups.

Stephen Grant says after he and his wife argued one night, she left their suburban Detroit home and flew back early to her job in Puerto Rico, and he's been trying hard to find her for five days.

Macomb County Sheriff's Detective Pam McLean and her partner, Detective Brian Kozlowski, almost immediately believe something's amiss.

"When we first got to the house, Stephen's very nervous, he was very fidgety, he was trying to be over-cooperative," said Det. McLean. "And the more questions we started asking him the more nervous he became."

But being nervous doesn't make someone guilty, and Tara is still just missing. So detectives also look at others, wondering if another lover is connected to her disappearance.

Or what about the nanny? She and Stephen had been getting close in the days leading up to Tara's disappearance.

"Their relationship had began approximately four to six weeks prior to Tara's disappearance, and it was escalating quickly," said Det. McLean.

The children were home sleeping the night their mother disappeared, but Verena, the nanny, was out. As the investigation continues, detectives are watching Verena and Stephen.

"We set up surveillance on him," said Det. McLean. "We knew something wasn't right and we believe he had something to do with it."

In the meantime, Stephen is busy playing the distraught husband, becoming a regular on the evening news.

Are people buying it?

"It was an Oscar-worthy performance," said author Andrea Billups. "This is a guy who is now the star of the 'Stephen Grant Show' -- 'Poor me.'"

Detectives are watching and closing in, chipping away at Stephen's implausible story.

"We found out that she wasn't back in Puerto Rico, we had checked all the airlines, we knew her passport had not been used, we knew her credit card had not been used, and the cellphone records show when her last call was made," said McLean.

Then investigators catch a break when a woman walking through a local park sees a baggie tucked into a tree filled with some questionable items.

"Gloves, metal shavings and blood. We later learned that it was in fact Tara's blood," said McLean.

A bombshell. Police arrange to have the rest of the park searched at the same time staying on Stephen.

"At this point in time Stephen had become somewhat uncooperative with us," said Det. McLean. "All of our questions we had, or anything, had to go directly through an attorney. He had refused to take a polygraph for us. We later learned that he had taken a private polygraph, and that it came back as inconclusive."

Three weeks after Tara went missing, detectives get a search warrant for the Grant house. A knock at the door brings a team of investigators.

"He was there in the beginning of the search when we got there," said McLean.

Then Stephen asks if he can take the dog for a walk.

"He was then free to leave," said McLean. "He was not being detained by us at that time."

As Stephen walks out of the house and into the cold winter night, the case takes a gruesome turn.

"We were all standing in the garage and my partner noticed this bin, and it looked a little out of place, and he opened it up and he could see that there was a lot of plastic in there, and he kind of poked at it and he could feel a little give, and he's like 'That does not feel right,'" said Det. McLean.

Detectives cut open the plastic.

"Inside the bag were the clothed remains of Tara Grant, at least part of her," said author Andrea Billups. "Her torso, from the neck to the top of her thighs, face-up. She had on her bra, panties and part of the slacks that she had been wearing. Tara Grant was dead. And part of her was in her own garage."

"My first thought or feeling was 'We got him,'" said Det. Pam McLean.

Stephen Grant went on the run.

"He knew we were going to find it, and that's when he went on the run," said Det. Pam McLean.

A manhunt for Stephen Grant is launched.

"The FBI is swarming the state, setting up a dragnet, a full-on search for him," said author Andrea Billups.

A suicidal Stephen Grant borrows a car from a friend and heads north into the frigid Michigan night.

"He makes this meandering trip all over the state of Michigan, and he remembers that he and Tara used to camp at Wilderness State Park," said Billups.

As he makes his way there, Stephen arms himself with alcohol, pills, razor blades -- and something else.

"He's purchased a toy gun thinking that if he had a gun in his hand and he aimed it at police, they would shoot him," said Billups.

After driving for hours a desperate Stephen makes some final calls and writes his two young children goodbye letters.

"He knew he wasn't going to win," said Det. McLean.

He was right.

"His vehicle was located up at the park and he was found out lying underneath a tree," said Det. McLean. "He had extreme hypothermia, semi-conscious. He was seeing people and talking to trees. He was in pretty bad shape. He was then airlifted and then taken to the local hospital."

Once Macomb County Sheriff's Detectives McLean and Kozlowski arrive, they place Stephen Grant under arrest. He wants to talk. Only their audio is recorded.

Little do detectives know the extent of the savage secrets Stephen's been hiding.

Stephen says it all started in their bedroom, when Tara was unpacking from her work trip and he was naked, getting ready for bed. A fight about Tara's busy work and travel schedule ensues. The argument quickly escalates. Tara slaps him across the face, then Stephen hits her.

"She fell," Stephen Grant tells detectives in the audio recording. "I know that she banged the back of her head on the floor, and then she said something like 'That's it. I'm gonna take the kids. You're going to be f------ homeless. You're a piece of s---.'"

Enraged, Stephen does the unthinkable.

"I choked her. I put my hands on her neck and choked her," Grant tells investigators. "She finally grabbed my hand at one point but it was too late then. I couldn't stop then. I knew I was going to prison. I panicked."

"She was looking into his eyes and she was fighting with him, and he grabbed a piece of clothing and put it over her face so that he didn't have to see her while he was killing her," said Det. McLean.

After more than four minutes of strangling, Tara Grant is dead.

Then, with their small children sleeping just feet away:

"I wrapped something, a belt around her neck, I think it was my brown leather belt," Grant says in the recording. "I knew I couldn't carry her, so I wrapped that around her neck and I used it to basically pull her downstairs."

Grant, still naked, drags Tara's body into the freezing cold garage where he struggles getting her into the back of her own truck.

"I dropped her," Grant tells detectives. "It was the most disgusting noise, it just sounded like dropping a watermelon on the cement. I knew then that I had killed her."

He eventually gets her into the SUV.

"He put it in the back of her SUV and shut the door and went back into his house," said Andrea Billups.

Moments later, the family's nanny Verena, with whom he had had a flirtation with, walks in the door. Grant quickly dresses then tells her the story he's concocted, that he and Tara fought and she walked out on him.

"He wanted the nanny to feel sorry for him, playing the 'Oh, my wife has left me' card," said Billups.

Then Grant begins a plan to cover his tracks, calling Tara's phone to leave messages.

The next day, Grant's scheme takes a grisly turn. After saying goodbye to his kids, he drives Tara's car with her body in the back to his father's machine shop.

"He lays out a bunch of tarps on the floor and he removes her body and places her on top of it and he begins to dismember her," said Billups.

When he finishes, he wraps the body parts in plastic and fills a large plastic bin to the brim -- with Tara. Early the next morning, Grant grabs his kids' sled and heads out into snowy Stony Creek Park. While standing on a hill, he puts the bin on top of the sled.

"It was like 'Keystone Kops,'" Grant tells detectives. "The sled took off and now I'm chasing after the sled that has my wife's cut-up body in it down a hill. I finally got it stopped when it fell over and it broke. So now all these pieces have now fallen all over the place."

Stephen Grant eventually gathers Tara's mutilated body parts and buries them around the park.

"He was hoping that the wildlife within the park would eat the remains and therefore would just leave bones, which would make it a little easier to avoid detection," said Det. McLean. "He moved her multiple times to multiple locations."

"I did a very, very bad job of hiding anything. It's right there in the open," Grant told detectives on tape.

Detectives also learn from Grant what led to their big break of finding Tara's torso in the family garage. When Stephen Grant heard that there was going to be a large-scale search of the park, he panicked, afraid the poorly hidden torso would be easily found.

"He first removed it from the park, then took it to his father's business and he put it on top of the office area," said Det. Pam McLean. "It remained there for approximately a day, at which time he moved it, because he was afraid it was going to start smelling, and then that's when he took it to his garage."

That was also when detectives showed up with their search warrant.

"Our timing was just right," said McLean. "Fortunately for us he had just moved her torso back there the night before."

Investigators would eventually locate most of Tara's remains, but not all.

"I believe there were 14 parts but they only recovered 11," said Andrea Billups.

They found some of the saw blades Grant used.

"We recovered some with some of Tara's flesh still on them," said McLean.

Detectives now know Stephen Grant did this despicable act all by himself. The nanny had nothing to do with it.

Nine months after Grant was arrested for the brutal slaying of his wife, the case goes to trial. And after three weeks of testimony, Stephen Grant is found guilty of second-degree murder and mutilation of a corpse. He's sentenced to 50 to 80 years in prison.

Six months after the trial, Grant's father committed suicide. There were reports he was seeking visitation rights at the time for his grandchildren. Those two kids went on to live with Tara's sister. Every year they attend Tara's Walk, which raises money for domestic abuse programs.