The man accused of killing a pregnant Montgomery County teacher will not be charged with killing the unborn fetus, officials announced Friday in a press conference.

Tyler Tessier was charged in the killing of Laura Wallen, his pregnant girlfriend, last month.

On Friday, officials said Wallen was 14 weeks pregnant at the time of her death. Tessier will not be charged with a second count of murder related to the child because officials say the child was not viable independent of Wallen.

Viable independent means the development of organs to be capable of surviving outside the uterus, according to Merriam-Webster.

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Prosecutors said they believe the motive behind the murder of a Maryland high school teacher was a love triangle.

Tessier admitted to police that he was engaged to another woman, court documents show. Both women were aware of each other, however, believed they were dating him exclusively.

The investigation reveals that at the end of August, Wallen sent the following text message to Tessier's fiance:

"It's important that some things are cleared up, and I would imagine that if you were in my position, you'd want some answers as well. By no means is this an attempt at confrontation, just looking for an explanation...woman to woman."

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Prosecutors believe the love triangle between Wallen, Tessier and his fiance was the probable motive behind the killing. Wallen's attempt to get in touch with the fiance may have also played a role in her murder.

Court documents revealed Wallen's best friends were also led to believe that another man had fathered her baby. According to court documents, Tessier sent messages to them pretending to be Wallen, stating that she was worried that somebody else was the father.

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Furthermore, one of Wallen's best friends received a series of text messages from her on September 2, court documents show. Wallen sent a text to her best friend saying that Tessier had taken her to a field and she didn't know why. She then sent a picture of the giant field with a tree line. Authorities think the image was on the same field where her body was later found.

Tessier went back to that field at least ten times since Wallen went missing, according to the investigation.

Wallen last contacted her family on September 3, officials said. Her body was found later in a shallow grave in the Damascus area.