The new Scott Peterson? Man busted in death of pregnant girlfriend, 15 years after notorious murder case

Tyler Tessier was all broken up at an emotional press conference four days ago in Maryland, but cops now believe he is the killer, and his tears were all an act.

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At the time, Tessier's pregnant girlfriend, Laura Wallen, of Olney, Md., was missing and he was making a public appeal, even holding hands with his girlfriend's mom as they announced a $25,000 reward for information leading to her safe return.

“I pray that she's safe and comes back,” he said at the press conference. “Laura, if you're listening, it doesn’t matter what’s happened. It doesn’t matter what the trouble, it's nothing we can't fix together.”

Cops say it's all a sick act. They say Tessier murdered the beloved high school “Teacher of the Year” and buried her in a shallow grave. Just like Scott Peterson 15 years ago, he allegedly didn't want to be a dad.

Tessier was arrested Wednesday afternoon and charged with murder.

In the days since Sept. 5, when the high school teacher failed to show up to work, Wallen's family, community, and Tessier rallied behind authorities working to find the mom-to-be.

The shocking slaying comes 15 years after the murder of pregnant Laci Peterson on the other side of the country, in California.

Coincidently, ABC is broadcasting a special documentary: Truth and Lies the Murder of Laci Peterson, hosted by Dan Abrams, on Thursday.

"People look at him and look at her and say: 'Could he have really done that? Really?'" Abrams told Inside Edition.

The documentary includes home video of Laci in a state of joy, seven months pregnant with the baby they were to name Connor. The nursery was ready and painted blue, decorated with a nautical theme.

Laci's mom, Sharon, recalls a chilling moment when she saw her daughter for the last time.

“She and I were sitting side by side,” Sharon told ABC News. “She leaned over and said, 'Scott doesn’t like to do this. I asked him to do this, when the baby kicks he doesn't want to touch my stomach.' That really, really bothered me.”

There is another disturbing similarity between the two cases.

Scott Petersen had a mistress, Amber Fry and Tessier was engaged to another woman and pregnant Laura had just found out, according to police in Rockville, Md.

"We were able to determine he was actually engaged to another woman and then we found another young lady that he had a relationship with also,” Capt. Darren Franke, who leads the Major Crimes Unit at of the Montgomery County Police Department, told Inside Edition. “Because of the double life, triple life he was leading — I think with the pregnancy of Laura — I think was collapsing around him.”

Read: Boyfriend Arrested for Alleged Murder of Pregnant Teacher Found in Shallow Grave: Cops

Psychologist Jeff Gardere says murder is one of the leading causes of death among pregnant women.

"That individual who is the father of the child now is held to task," he told Inside Edition. "They now have to step up and if that person is not emotionally balanced, this kind of situation pushes them over the edge."

Prosecutors are determining whether or not to charge Tessier in the death of his unborn baby.

Scott Peterson was convicted of double murder. He is currently on death row at San Quentin State Prison.

Watch: Missing College Student's Remains Found in Shallow Grave, Boyfriend Charged