The peaceful night of Feb. 2, 2014, in Coppell, Texas suddenly erupts in panic. Police receive a 911 call reporting a man has shot himself.

The answers won't come easy, but one investigator is determined to uncover the truth and get justice once and for all.

Just one week before the desperate 911 call, it was moving day for Jonathan Crews. The 27-year-old urgent-medical-care director was moving out of his parents' home and into his first very own apartment.

"He gotten a new car recently, and he was just really happy with where he was going," said Dani Crews, Jonathan's sister.

And right by his side is his girlfriend, 26-year-old martial arts instructor Brenda Lazaro. Dani actually introduced the two of them.

"She was a good friend of mine for about two years," said Dani Crews.

The two women first met at a local martial arts school where Brenda taught and Dani attended classes. Soon her brother joined the same studio, and once he laid eyes on the beautiful instructor, the rest was history.

"He told me that he was interested in her," said Dani. "He actually asked for my permission to ask her out, 'cause he knew she was my friend and he didn't want to get in between that."

With the blessing of his sister, Jonathan and Brenda start dating. It's a whirlwind romance.

"He was the kind of guy where he fell hard," said Dani.

And even though the lovebirds have been dating only a of couple weeks, the conversation quickly turns to marriage and children.

"He really wanted to be a dad," said Pam Crews, Jonathan's mother. "His whole life he really looked forward to being a father some day."

But before Jonathan can be certain Brenda is the one for him, he wants his best friend from college Jacob and Jacob's girlfriend Emily to meet Brenda.

What was Emily's first impression of Jonathan's new girlfriend?

"I would say that she was probably the most unfriendly that I had met of all of them," said Emily Ramsey. "She didn't talk very much and at that time I didn't know anything about her, I just kind of assumed that she was really shy."

It bothers Jonathan that the dinner with his friends didn't go very well. But his date night is about to get even worse, when on the ride home Brenda Lazaro goes from seemingly shy to flat-out furious. Her reason?

"He had hugged Emily," said Pam Crews.

Their huge fight was over an innocent hug with his best buddy's girlfriend.

"He didn't understand. He was very confused," said Pam.

Two months pass and Jonathan and Brenda's relationship appears to be back on the upswing. That is until Brenda reveals that she's still holding a grudge about the hugging incident. And now she's making demands.

"That was the first glimpse of the jealousy that I ever saw," said Dani Crews.

It's a Saturday afternoon and Dani is in a martial arts class when she gets a text from her brother.

"He was saying that Brenda was going to make him choose between the two of them," said Dani.

Sunday morning, Jonathan meets his best friends Emily and Jacob for brunch.

"He told Emily that Brenda had an issue with her," said Dani.

And suddenly Brenda is blowing up Jonathan's phone. Brenda appears to be coming unhinged.

"She had kind of gone off the rails," said Emily Ramsey tells Crime Watch Daily. "How dare I put my hands on her man and that I better not do that again. I told her, 'I'm so sorry if you have a problem with that, but he's my friend, I'm gonna hug him if I want to, you know, that's crazy.' I don't really know another way to describe it, except for just so crazy."

Then abruptly the call is over.

"At that point he was done," said Emily. "'I'm just done, I'm breaking up with her.'"

Emily and her boyfriend Jacob drop off Jonathan at his apartment.

"I gave him a hug and Jacob gave him a hug and we just told him we loved him," said Emily.

They don't know it at the time, but it was their last conversation with Jonathan Crews.

Now, late Sunday afternoon around 4 p.m., Brenda comes over to Jonathan's apartment so they can talk. And according to his friends and family, this is the night he plans to tell her it's over. Then around 11 that night, Emily receives a very dark text message from Jonathan's phone.

"That said 'I want to die, period,'" said Emily.

Emily has no idea what to make of it. She texts Jonathan right back.

Tragically, Jonathan Crews is not OK -- he's dead.

Just 30 minutes after that text from Jonathan's phone to Emily, a 911 call comes in to the Coppell, Texas Police Dept. from Brenda Lazaro.

Lazaro: "We were just having a discussion and we were just talking, and he just said that he loved me. And I didn't believe him. He said he was gonna prove that he loves me. I didn't know that he had a gun."

Jonathan Crews, 27, is dead in his apartment from a single gunshot. His girlfriend Brenda Lazaro claims he shot himself.

In minutes, police are on scene and find the distraught girlfriend standing in the apartment parking lot.

"She was screaming and crying," said Jonathan's sister Dani Crews.

Officers ask her what happened. Brenda explains to them that she and Jonathan were arguing about his friend Emily.

"She was really upset that he had hugged Emily," said Jonathan's mother Pam Crews. "She was just furious over it."

It appears Brenda Lazaro can hold a grudge: That innocent hug with one of his best friends Emily happened months prior.

"There's this running argument about how much Jonathan loves Emily, and -- are you kidding me? It's so beyond rational," said Jonathan's father John Crews.

During this final and fatal argument, Brenda tells police she was sitting on the floor at the foot of the bed and Jonathan was under the covers. Then, according to the police report, Brenda tells cops Jonathan suddenly exclaimed, "Baby, I love you and I'm going to show you that I love you."

"Then all of a sudden she hears this 'bang,'" said Pam Crews. "Brenda says Jonathan shot himself."

Then Brenda drops this bombshell:

"She said she was breaking up with him," said Jonathan's sister Dani.

And when police discover his final cellphone text, which reads "I want to die," it appears to corroborate Brenda's story. Then Jonathan's family arrives on scene.

"I walked up and there was a police officer and they wouldn't let me in the apartment, and I asked him three separate times if he was sure that Jonathan was dead, and he said he was," said Jon Crews.

It's heartbreaking news for the Crews family, and the story of a lovesick suicide makes it even worse.

"Why would he shoot himself?" said Pam Crews. "It doesn't make any sense that he would do this. I thought maybe an intruder had come in and shot him, and then Brenda found him that way and thought he'd done it."

But according to a police report, there's no intruder, just Brenda in the apartment when Jonathan is killed.

Detectives have another theory: Could this be a tragic accident? Their report reveals the magazine clip for the gun was in a drawer in a different room, and investigators believe Jonathan had no idea a round was actually in the chamber of the 9-millimeter pistol when he pulled the trigger.

At that point, the Crews family says, there was no reason to doubt Brenda's story.

"Even that night after we got back from his apartment and all that, I thought even no matter how mad she is at him, she always talks about how much she loves me, so she wouldn't do that to me, surely," said Dani Crews.

So if Brenda didn't do it, then that leaves Jonathan. But his family says the 27-year-old doesn't exactly fit the profile of someone who is suicidal.

"He was just too happy, too looking forward to the future. Too good of a place in his life. Too rational," said Pam Crews.

Despite what his mom says, a police report reveals Jonathan had a history of depression. And according to the report he was supposed to be on anti-depressants, but he wasn't taking them.

Trying to find out exactly what happened, investigators begin to process the crime scene. The police affidavit reveals that officers on the scene found the victim lying in bed with blood and a semiautomatic pistol on his left side -- strange because Jonathan is right-handed.

The affidavit also reveals what appears to be a single gunshot wound around his heart -- odd because most men who commit suicide shoot themselves in the head or the mouth.

While crime-scene investigation teams finish collecting evidence, an officer outside the apartment building with the Crews family makes a curious comment.

"He said 'If it's any consolation, this isn't something he intended for himself,'" said Dani Crews.

Dani, still in shock over her brother's death, doesn't ask the cop to explain. But she wonders, Is there something she doesn't know about her good friend Brenda?

"My mind was foggy and I didn't really pick up on the red flag of that until later," said Dani.

On the morning of her brother's funeral, Brenda Lazaro is a no-show. Then, out of nowhere, Brenda sends a series of furious texts to Dani.

"She told me she was upset because she hadn't been asked to talk at the funeral, which was kind of weird because she'd only known him for a few months," said Dani.

Now, suspicious that Brenda could have been involved in their son's death, the family hires private investigator Sheila Wysocki.

"Pam and John called me and told me about their son's case, and I asked them to send me all the documentation on it," Sheila Wysocki tells Crime Watch Daily.

Once Wysocki gets her hands on the police reports, she creates three animated scenarios of the night in question. The first is what Brenda told police happened that night; the second, what Jonathan's sister says Brenda told her; and the third is animation done by the P.I. in what she says the forensics reveal. (Animation by Gray Hughes)

The results?

"The smoking gun is the gun," Sheila Wysocki tells Crime Watch Daily.

Jonathan Crews is dead from a single gunshot to the heart. His girlfriend Brenda Lazaro was the only other person in the apartment when the 27-year-old Crews was shot. She claims he did it to profess his love for her. But now Jonathan's grieving family believes Brenda is a liar, and that she's the one who pulled the trigger in a jealous rage.

Jonathan's father John Crews takes his suspicion to the Coppell Police Department. He wants to know if police are investigating his son's death as a suicide or murder. And he's not asking just as a concerned parent, but as a former trial attorney with more than 30 years' experience building and prosecuting cases.

"I looked the detective in the eye, I said 'I need you to tell me your confidence level that she is the one who pulled the trigger,' and he said 'In excess of 90 percent,'" John Crews tells Crime Watch Daily.

In the search warrant from the night of the shooting, investigators write that they were pulling evidence pertaining to a suspected murder.

"It became crystal-clear that the police thought this was a homicide," said John.

"And I remember thinking 'Well, they'll arrest her then,'" said Jonathan's mother Pam.

Jonathon's family waits and waits -- but police don't make an arrest. Then the final finding from the coroner is a punch straight to the gut: Jonathan Crews's cause of death was undetermined.

"I'm not sure what happened exactly," said John. "I think there was some miscommunication with the medical examiner."

After several months it appeared the case had stalled.

"It's open but inactive, as I understand it," said John.

Meanwhile, the private investigator they've hired is hard at work piecing together what she believes really happened that night.

The crime scene photos show Jonathan's hands were covered in bags to preserve evidence. The P.I. points to the results of the gunshot residue collected that tragic night from both Jonathan and Brenda. Wysocki didn't conduct the tests, but claims what she read in police reports is baffling.

"There was no gun residue on Jonathan's left hand," said Wysocki. "On the right hand, it's not even enough to raise eyebrows."

And Brenda Lazaro?

"It was all over her," said Wysocki. "Brenda had gun residue on both of her hands, according to the record, and her hoodie, or what she was wearing."

According to Wysocki, there is something else that stands out, as seen in an animation re-enactment of Brenda Lazaro's statement to police (Animation by Gray Hughes). On the night in question, Brenda claimed she was sitting at the foot of the bed and Jonathan was in bed.

"A person that's going to commit suicide generally doesn't dress for bed, get in, pull the covers up and shoot themselves," said Wysocki.

In a second animation created by Sheila Wysocki's team (Animation by Gray Hughes), they re-enact another version of events from that night, a story Brenda told Dani.

"She told me he was standing up facing her and he shot himself," said Dani Crews.

But Wysocki says that can't be true because according to police reports, Jonathan was found dead in bed under the covers.

"I guess he fell into the bed, covered himself up and rolled over -- I mean it just, none of it makes sense," said Wysocki.

And then there's the final resting position of the gun.

"When you shoot a gun there's just a little kick, it doesn't neatly settle right next to your body pointing at your toes. It's lined up -- that doesn't happen," said Wysocki.

And in a third animation (Animation by Gray Hughes) that follows the forensics -- namely, the trajectory of the bullet to create the wound he sustained -- Sheila Wysocki says it shows it would be physically impossible for Jonathan Crews to shoot himself.

"He couldn't have done that angle without breaking his wrist," said Wysocki.

And then there's where he was shot.

"The angle was right at his heart, and I believe she was shooting him in the heart because he broke her heart," said Wysocki. "He didn't see it coming."

Nor hear it coming, according to Jonathan's mother Pam, who tells Wysocki and police that after the shooting, a fourth pillow was missing from her son's bed.

"There were some particles on his shirt that look like there may have been something held between him and the gun, and I started asking the police very early on, 'Where is his fourth pillow?' And they didn't have an answer for me," said Pam Crews.

Then, perhaps the most damning evidence against Brenda Lazaro, there are her own words from her 911 call she made on the night of the shooting.

911 Operator: "Did he mean to do it? Did he do it on purpose?"

Brenda Lazaro: "No. Yeah, he did on purpose."

"In the 911 call, there's a phrase that the 911 operator asked, 'Did he mean to do it to himself,' or 'Was it on purpose?' Her answer was no, and then she immediately changed it to yes. I think the no was very telling. I think the no was a truthful statement," said Sheila Wysocki.

Finally, after a long, painful investigation, the Crews family and the private investigator turn over all of their findings to police. John Crews says police were not receptive.

Crime Watch Daily reached out to the Coppell Police Department several times. A spokesperson there told our producer the department is not doing any on-camera interviews on this case. That spokesperson did agree to send a written response. We have not received any from Coppell P.D.

That's particularly frustrating for Jonathan's father, a man who knows the ins and outs of the justice system.

"You know, we thought that this was going to take a long time," said John Crews. "We thought it would take a year. Now we're almost four years into it. It's shocking."

Four years later and few answers about what happened to their son. Running out of options, the Crews family files a civil suit against Brenda Lazaro.

"We just want the truth to come out," said Jon Crews.

Preparing for the civil trial, private investigator Sheila Wysocki interviews people close to the case. And there's one man who was never interviewed by police, but who seems to have a lot to say about Brenda Lazaro.

"Almost ruined me," said Matthew Kirk in a recorded deposition.

Matthew Kirk is Brenda Lazaro's ex-boyfriend. They were together for almost five years, and according to his taped deposition, they have quite a volatile history.

"She was jealous of any woman I talked to," Kirk said in a deposition. "She just got crazy whenever I went around any girl."

So jealous that she didn't want him to even hang out with his own sister-in-law. In fact, when Kirk's brother and sister-in-law had a baby, he had to sneak out to visit his newborn niece.

And when Brenda found out?

"She was cutting herself in my bathroom. She was crying, and her hand was full of blood," Kirk said in the deposition.

"Matthew painted a very unstable, erratic kind of psycho woman, and he painted a very jealous woman," said Sheila Wysocki.

"We have this jealous, violent, irrational person, and we have Jonathan, who said 'I've had enough of this. I'm gonna break up.' And she pulled the trigger," said Jon Crews.

Despite Matthew Kirk's dark depiction of Brenda Lazaro, he also said "I don't think of her as the type of person that would really kill somebody."

To date, Brenda Lazaro has never been charged, and has denied any involvement in the shooting death of Jonathan Crews. She maintains Jonathan shot himself. And remember, one report from detectives at the scene called it an accident.

Today Brenda continues to teach at the same martial arts studio where they met. We requested an interview, but she declined.

But Crime Watch Daily reached out to Brenda's attorney Andrew Jee, who stated: "We deny the allegations against her and look forward to proving this to the jury."

This civil trial of love gone horribly wrong is scheduled for February 13, 2018, the day before Valentine's Day.

What does justice look like for the Crews family?

"I don't think we're concerned that much about what that ultimately looks like, as long as a jury says 'This is the truth of what happened,' and preferable a criminal jury, because that's where this belongs," said John Crews.