RICHMOND, Va. (AP) — Two years after a 13-year-old Virginia girl was found stabbed to death, a former Virginia Tech student is going on trial in her killing.

David Eisenhauer’s first-degree murder trial in the 2016 death of Nicole Lovell begins Monday in Montgomery County Circuit Court in Christiansburg. He has pleaded not guilty.

Prosecutors say Lovell, of Blacksburg, climbed out her bedroom window one night in January 2016 to meet Eisenhauer, who was then 18 and a freshman engineering student at Virginia Tech. The pair had communicated through an instant messaging app.

Three days later, her body was found just over the state line in North Carolina.

Eisenhauer, of Columbia, Maryland, admitted meeting her but told police he left when he saw how young she was.

His friend, Natalie Keepers, told police that Eisenhauer killed her to keep her from exposing their inappropriate relationship. Keepers, of Laurel, Maryland, is also a former Virginia Tech student and has been charged as an accessory in Lovell’s death. Her trial is scheduled for September.