The boyfriend of a missing pregnant teacher from Montgomery County was arrested for her murder on Wednesday, according to Montgomery County police.

The body of Laura Wallen, 31, was found around noon in a wooded area in Damascus, Md. in a shallow grave.

Her boyfriend, Tyler Tessier, was arrested for Wallen's murder. Police say Tessier made several visits to the area where Wallen's body was found.

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Once police started investigating, they found tire tracks that led to the location of Wallen's body.

Wallen last contacted her family on Sept. 4 via text message. Police say it was later determined that those texts were sent to Wallen's sister by Tessier.

Tessier spoke at a press conference on Tuesday with Wallen's family. Police say the press conference was a calculated move to see how he would react.

Police found Wallen's truck abandoned in an apartment complex off of Gramercy Place near Columbia Mall last Thursday.

On Wednesday, Sept. 13th, police said Tessier had driven the victim's car to the Columbia area and took off the front tag.

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Police also said Tessier had asked a friend for help "to clean up a mess" after his girlfriend went missing.

Investigators are not saying what they found inside of Wallen’s condo or in her car.

The Wilde Lake High School teacher never showed up on the first day of school, and the last time family members heard from her was in a text message on Labor Day.

Wallen's boyfriend, who she's known for 10 years, said she is four months pregnant and excited to have a baby.