A De Soto man charged with raping three teen girls after a monthslong investigation by Festus police may be responsible for more crimes, police said.

Matthew Allen Baker Jr., 19, was arrested July 7 on two charges of first-degree rape and one charge of first-degree statutory rape with a person less than 14. He was being held in the Jefferson County Jail, where no bond has been set.

Festus Police Chief Tim Lewis said the female victims range from 13 to 15. It wasn’t immediately clear how the suspect encountered the girls.

Lewis said his department has been conducting a nine-month-long investigation into rape allegations against Baker. He said many of the victims were hesitant to come forward, and he believes there may be other victims who are embarrassed to talk about what happened to them.

Detectives believe the sexual assaults have been going on for years. Lewis said there are other potential victims in Festus, De Soto and Herculaneum.

“We have received numerous calls,” Lewis said. “We encourage anyone who has been forced to do anything by Baker to come forward.”

He encourage possible victims to call Festus police at 636-937-5184.