A Criminal Court jury convicted Cornelius Monger, 36, on Thursday evening of statutory rape by an authority figure, sexual battery by an authority figure and incest.
He was taken into custody and will be sentenced Jan. 15 by Judge Glenn Wright.
Monger was a Memphis police officer from July 2006 to April 2013 when he was fired.
According to testimony, Monger began sexually molesting his adopted sister when she was 15 years old and that the assaults continued for several years until she moved out of the house in 2012.
In April of this year, Monger’s father, Henry Monger Jr., 64, pleaded guilty to raping the same victim and two of her sisters, all of whom he and his wife had adopted.
One of the victims was 10 years old when Henry Monger began raping her, investigators said. Henry Monger is serving a 15-year prison sentence.
His wife, Barbara Monger, 65, is charged with coercion of a witness for allegedly telling the girls later not to cooperate with officers investigating her husband. She is set for trial in February.
The case this week was handled by Carrie Shelton, chief prosecutor of the DA’s Special Victims Unit (SVU), and by Asst. Dist. Atty. Jessie Banti, also of that unit.
SVU prosecutes cases of child sexual abuse and severe physical abuse of child victims; rape and aggravated rape of adult victims, and abuse of elderly and vulnerable adults.
The SVU reviews child-victim cases with Shelby County’s multi-agency Child Protection Investigative Team.