HIGHLANDS RANCH, Colo. - A former Douglas County teacher and coach has been arrested and accused of sexually assaulting a female student, authorities said Wednesday.

The Douglas County Sheriff's Office Special Victims Unit arrested Richard Lee Johnson, 31, of Englewood, on Tuesday after he turned himself in on an arrest warrant, said sheriff's spokesman Sgt. Ron Hanavan.

Detectives have filed a case with the 18th Judicial District Attorney's Office seeking 30 felony charges against Johnson, including sexual assault on a child by one in a position of trust, sexual assault on a child, sexual exploitation of a child and enticement of child.

Johnson is a former eighth grade teacher at Rocky Heights Middle School and was a former boys basketball coach at Rock Canyon High School. Both schools are in Highlands Ranch.

The arrest stemmed from an investigation that started in June 2012, Hanavan said.

State court records indicate the alleged sexual assault on a female student occurred in 2010.

Johnson left the school district in March 2012 and is not currently employed as a teacher, Hanavan sasid.

Detectives are asking anyone who has information on the investigation to call Douglas County Sheriff's Detective Dea Aragon at 303-814-7131.