Childhood friend of Laura Wallen: 'She just had the biggest heart, and he just took that away'

Before police announced that Laura Wallen's body had been found in a shallow grave in Montgomery County on Wednesday, FOX 5 was contacted by one of Wallen's close friends who told us that her Wallen's boyfriend, Tyler Tessier, was engaged to another woman.

FOX 5 was the first station to identify and make contact with the other woman Tessier was engaged to, but we kept this information under wraps to not jeopardize the police's investigation.

RELATED: Autopsy: Slain pregnant teacher Laura Wallen was shot in back of the head

Chrysanthia Miller, one of Wallen's childhood friends, shed more light on Wallen and Tessier's past and how he had managed to keep his double life from the 31-year-old pregnant teacher for so long.

"Being a mom, that was her goal in life," Miller said. "That was like her mission and you could tell that there was a sense of calm that came over her when she found out that she was pregnant."

Miller said she never expected her childhood best friend would end up dead, allegedly at the hands of the father of her unborn child.

"He is a monster and he is a liar," said Laura's father, Mark Wallen, on Thursday.

"Ever since watching the press conference from her dad [Friday], he said it was the only thing we ever fought over - Laura and I got in one argument in 17 years and it was over [Tessier] and that was the last I talked to her," said Miller.

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Chrysanthia and Laura met in tenth grade geometry class and have stayed close ever since. Chrysanthia said Laura and Tyler were on and off for the last six years and there were always signs that he was not being truthful - even living a double life. But he had the power to manipulate Laura.

The two best friends from high school argued last month when Laura told Chrysanthia that he was moving in with her.

"She said that she really wanted a relationship with Tyler to progress and they were talking about getting engaged," said Miller. "He had taken her to look at a ring."

According to court documents, authorities believe Tessier was engaged to another woman and Wallen had recently contacted her for a face-to-face meeting - possibly to tell her she was pregnant.

But that never happened as police believe Tessier lured Wallen to where she was killed with promises of a romantic adventure.

Meanwhile, Wallen's apartment door in Olney is now filled with flowers and prayers from people who loved her. The ones who were closest to her say they are heartbroken.

"She loved and she was a hopeless romantic," Miller said. "She was just thoughtful, creative and she just had the biggest heart, and he just took that away. I just want my friend back."

Sources said Tessier was engaged to be married to the other woman next April, just one month after Wallen's baby would have been due.

FOX 5's coverage on the disappearance of Laura Wallen:

Autopsy: Slain pregnant teacher Laura Wallen was shot in back of the head

Laura Wallen's murder linked to love triangle, police believe

Letting Tyler Tessier speak at Laura Wallen's news conference part of police strategy

Body of missing pregnant Maryland teacher found; boyfriend arrested

Missing pregnant teacher's family offers $25,000 reward

Vehicle of missing pregnant Maryland teacher found in Howard County

Students coming together to help in search for missing pregnant Md. high school teacher

Wilde Lake High School students hoping for safe return of missing teacher Laura Wallen

Search continues for missing pregnant Maryland teacher

Police searching for missing pregnant Maryland teacher