HARTFORD, Conn. (AP) — A Connecticut juvenile detention officer has been charged with sexual assault after police say he engaged in an "inappropriate sexual relationship" with a 17-year-old inmate.

State police say 40-year-old Marquis Marquez, of New Britain, was charged Tuesday after he turned himself in on a warrant for his arrest.

Authorities say an investigation into Marquez began in August. Court documents show the victim's mother reported the relationship to police after the victim told her younger sister.

Police say the sexual conduct happened at the Juvenile Detention Center in Hartford.

Marquez has been placed on unpaid leave.

He is scheduled to appear in court Dec. 12. It is unclear if he has an attorney.