A woman involved in the killing of a Johns Hopkins University researcher last year has been sentenced to 15 years in prison.

The Baltimore State’s Attorney’s Office says 25-year-old Lavelva Merritt was sentenced Monday. Merritt pleaded guilty earlier this year to robbery and conspiracy to commit robbery in exchange for her testimony against her then-boyfriend, John Alexander Wagner.

Wagner was convicted in August of first-degree murder and armed robbery in the stabbing death of 23-year-old Stephen Pitcairn. He has been sentenced to life in prison plus 20 years.

Pitcairn was robbed and stabbed last summer while talking on a cell phone with his mother. He had been walking home from Penn Station.