Man accused of killing pregnant Md. teacher won't face charges for fetus' death

No additional murder charges will be filed against the boyfriend of a pregnant teacher found dead in a shallow grave last month, Montgomery County State's Attorney John McCarthy said Friday.

Tyler Tessier is accused of killing Laura Wallen, a 31-year-old Olney woman who taught social studies at Wilde Lake High School in Columbia. Wallen disappeared in September after her family reported her missing on Labor Day.

Tessier appeared in court Friday morning for a preliminary hearing. After the hearing, McCarthy said that in order to charge Tessier with murdering Wallen's unborn child, Maryland law states he would have to prove that it was "viable" and able to survive on its own.

"Based on medical testimony, the child was not viable, independent of Miss Wallen. Based on those findings and as a matter of law in Maryland, the defendant is not chargeable with a second count of murder, related to the child," said McCarthy.

An autopsy determined she was 14 weeks pregnant when she died.

A week after she went missing, Wallen's body was found in a shallow grave at a secluded field in Damascus. Wallen's autopsy revealed that she had been shot in the back of the head. Tessier was later arrested after her remains were found.

Court documents say Tessier was engaged to another woman at the time of Wallen's death, and authorities have indicated they believe the motive behind the murder was connected to a love triangle.

McCarthy said if Tessier was convicted in the death of Wallen, the judge could consider the death of the unborn child at sentencing. If convicted, officials said Tessier could be sentenced to life in prison without the possibility of parole.

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

Boyfriend of pregnant Maryland teacher indicted on murder charge

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