BATON ROUGE - The assistant principal of a Baton Rouge magnet school pleaded not guilty on Tuesday morning to charges of first degree murder and first degree feticide for the murder of a pregnant school administrator.

39-year-old Robert Marks was arrested in June for shooting Lyntell Washington, a school administrator at Brookstown Middle School, where Marks was the assistant principal.

The two were having an affair and Washington was seven months pregnant with Marks' child at the time of her murder. Marks was married to another woman at the time.

Police found Washington's blood spattered in a car and her three-year-old daughter wandering around alone nearby. A week later, Washington's body was found in a sugar cane field in Iberville Parish. Marks was originally arrested for aggravated kidnapping and child desertion before charges were upgraded to murder and feticide.

Marks is currently on leave from the school and his next court date is Jan. 5.