A former Pennsylvania police officer charged with sexually assaulting two young girls more than two decades ago was killed early Wednesday during a gunfire exchange with police who recognized his vehicle and confronted him, according to Montgomery County District Attorney Kevin Steele.

Francis Connell Collier, 38, who resigned in December from the Morton Police Department in suburban Philadelphia after being placed on leave because of the investigation, was fatally shot at 3:48 a.m. in Bala Cynwyd, near his home.

A criminal complaint filed Tuesday in Delaware County accused Collier of child rape, endangering the welfare of children and related sex offenses. The victims were under the age of 13 at the time.

Collier failed a polygraph in early December and told a detective afterward “that he ‘never intentionally touched the girls inappropriately,’” police wrote in the probable cause affidavit.

Lower Merion Township officers on patrol knew Collier was facing criminal charges and saw him returning to his car, Steele said in a release.

“When they confronted him, Collier fired at the officers, who returned fire, fatally wounding Collier,” Steele said.

Morton police said Collier was put on unpaid administrative leave when prosecutors informed the department of the investigation in December. He resigned on Dec. 19, the department said in the statement posted online.

The affidavit says the two victims had seen social media photos of Collier with children and were both concerned to learn he was a member of a child abuse task force.

“The Morton Police Department is deeply troubled by the serious allegations against a former officer,” the department’s statement read. “The conduct described in the charges is profoundly disturbing and wholly inconsistent with the standards and values expected of those who serve our community.”

Collier did not have a defense lawyer on file, according to court officials.