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PLAQUEMINE, La. (BRPROUD) — A former Baton Rouge assistant principal was sentenced to life in prison on Thursday for the 2016 murder of a pregnant school teacher.

Robert Marks, 45, killed 40-year-old Lyntell Washington and her 7-month-old unborn baby in 2016. Both worked at Brookstown Middle Magnet Academy in Baton Rouge.

Through an investigation into Washington’s June of 2016 disappearance, detectives learned that she and Marks were in a romantic relationship and the unborn child was his. Washington’s body was later found by authorities in a ditch behind a sugar cane field on Hwy 77 in Rosedale. The East Baton Rouge Coroner’s Office determined Washington’s cause of death as a gunshot to the head.

Marks faced charges of second-degree murder, kidnapping and first-degree feticide.