Police: Howard County Teacher Was Shot In The Back Of The Head

Laura Wallen's father, Mark Wallen, speaks to the media, accompanied by mother Gwen and other family members. Credit: Phil Yacuboski

Montgomery County police say Laura Wallen, the missing Howard County teacher, was killed by her boyfriend.

Tyler Tessier, 32, was arrested at 5:30 p.m. Wednesday, two days after he appeared with her parents and made a plea for her safe return.

At a bail hearing Thursday, Tessier was ordered held without bail.

Montgomery County police Chief Tom Manger said Wallen was shot in the back of the head and Tessier buried her in a shallow grave on property that belonged to one of his friends. The weapon has yet to be recovered.

"He is a monster. He's a liar," Wallen's father, Mark, told the media after Tessier's bail hearing.

Montgomery County State's Attorney John McCarthy says it's "highly unlikely" they will add a second murder charge for Wallen's unborn child.

Wallen had been missing nearly two weeks when her body was found.

"We were praying for a good old-fashioned miracle, but God did not give us that miracle," Mark Wallen said. "She was a woman of faith. She's now in God's arms."

Wallen, 31, a history teacher at Wilde Lake High School in Columbia, was last heard from Sept. 4 at her condominium in Olney. She was four months pregnant.

"My heart goes out to the people who prayed so hard for her safe return and are devastated by this news," Howard County interim superintendent Michael Matirano said in a statement.

Police last week discovered her 2011 black Ford Escape parked in a gated apartment complex almost directly across a highway from the high school.

Members of the community handed out and posted paper fliers around Howard and Montgomery counties over the weekend showing the blond-haired, blue-eyed teacher with the words "MISSING" in red.

“She’s always willing to put her students first, so I know if one of us was in this situation, she would’ve been head-on attacking it and in the streets just like we are,” Saquan Maxwell, who organized the community effort, told ABC Washington, D.C., affiliate WJLA-TV Saturday.

“My heart goes out to her wherever she is,” said Madison Pearson, who told WJLA she had Wallen as a teacher in middle school and high school.

Video: Boyfriend charged in missing teacher's killing

Her body was discovered after police, while executing a search warrant a residence tied to an acquaintance of Tessier's on Prices Distillery Road in Damascus, they saw tire tracks into a field leading to what looked like freshly dug dirt. They went to the home on the neighboring plot and got access to that field, where cadaver dogs led police to find Wallen's body in a shallow grave.

Wallen contacted her sister in a text message Sept. 2, saying her boyfriend had taken her on an "adventure" to a field in the rural Damascus area, according to the Montgomery County Police Department. The sister told Wallen to take a picture, and she did, Manger said.

Police later obtained that photo and matched it to the property where Wallen's body was located, Manger added.

Manger said there were no obvious signs of trauma, and are awaiting the results of an autopsy to be conducted by the office of the chief medical examiner. As of Thursday afternoon, McCarthy said, that autopsy had not yet been completed.

"There are so many people, so many people that miss you. There are so many people that are out. We haven't slept. We haven't eaten. We are just looking and praying that you're safe. I'm asking, just let us know that you're safe," Tessier said Monday, when he accompanied the family to an event where the Wallens offered a reward for information on her whereabouts.

At that very moment, however, he was a person of interest, and the family knew it.

"The decision to allow him to participate in that news conference was a calculated decision made by the detectives... to hear what he has to say," Manger said.

Police said they were aware of inconsistencies in what Tessier had told officers and, questioned by them on Wednesday, admitted to certain aspects of the case. Manger said Tessier's believed to have driven Wallen's car to Columbia, and that Tessier admitted to disposing of the car's front tag, as well as Wallen's driver's license and iPhone.

In fact, Manger said texts sent from Wallen's phone on the morning of Sept. 4 were actually sent by Tessier. He said police believe Wallen was killed the previous day. The two were seen together in surveillance footage at a grocery store near Olney's home on Saturday, Sept. 2.

Raw Video: Police announce arrest of boyfriend in teacher's killing

Police say Tessier also called an acquaintance that weekend and asked him to help "clean up a mess," an offer the friend turned down.

As far as a motive, Tessier was the father of Wallen's unborn child, but he was engaged to another woman.

"Obviously, there was a triangle going on here. He was involved separately with two women, one of whom he was engaged to, the other of whom he was out looking at a house," Montgomery County State's Attorney John McCarthy said.

"He has been deceiving and lying their entire existence. Their relationship was the only thing that Laura and her family ever fought about," Mark Wallen said.

Charging documents say Tessier also used Wallen's phone to text her sister, trying to throw police off the case, insinuating he was not the father of the child.

"I am, like, 95 percent sure Tyler is not the father," he wrote posing as Wallen, among other suspicious texts.

The Howard County mobile crisis team will be at Wilde Lake High School Wednesday evening to provide support to the entire Wilde Lake community. There will be large teams of people available at Wilde Lake High School and Murray Hill Middle School on Thursday to support every student and staff member that need somebody to talk to.

Phil Yacuboski and ABC News Radio contributed to this report.