A former St. Louis County high school teacher suspected of raping a student in the mid-1970s apparently approached police because he thought he could not be charged in the case, Prosecuting Attorney Bob McCullough said.

Donald Ingerson, 67, is charged with one count of rape and one count of second-degree statutory sodomy.

He taught at five or six school districts in St. Louis County beginning in the 1960s and continuing into the 1990s, McCullough said Tuesday during a news conference at the Buzz Westfall Justice Center in Clayton. McCullough declined to identify the districts, though he said districts where the suspect worked have been notified and asked to contact police should additional victims come forward.

It does not appear that Ingerson ever worked for the the Maplewood Richmond Heights School District, director of communication Brian Adkisson said. Police have not contacted the district about the case.

Florissant Patch has confirmed that Ingerson once worked in the Ferguson-Florissant School District. Eureka-Wildwood Patch confirmed he once was employed with Lafayette High School.

Two victims, both students at the time of the incidents, have been identified so far, though McCullough said his work in similar cases leads him to think there are others. Ingerson is suspected of having had multiple sexual encounters with both, McCullough said, the first between September 1974 and January 1976, and the second between Jan. 1, 1995 and Nov. 17, 1996.

McCullough said he thinks the encounters happened at different locations outside of school grounds.

In early June, Ingerson called the St. Louis County Police Department to say he had something to discuss, McCullough said. He spoke with investigators.

Ingerson, who lives in Ely, MN, near the Canadian border, arrived in St. Louis on Sunday and repeated statements about the sexual encounters to police on Monday, McCullough said. At that time, McCullough said, Ingerson was arrested.

Ingerson did not appear to realize that the statute of limitations had not expired, McCullough said.

Both victims have been contacted and have been cooperative. Police previously had not heard of either the victims or Ingerson, McCullough said.

McCullough said Ingerson moved to Minnesota sometime after he retired from teaching.

He is being held in the St. Louis County Jail on a $300,000 cash-only bond.

People who think they might have been victims of a sexual crime are asked to call St. Louis County detectives at 314-880-2341.