An Ohio prisoner and a woman became pen pals while he was behind bars, and now he's accused of killing her.

Thomas Knuff got out of jail in April and stayed with Regina Capobianco and John Mann.

Weeks later, police say, he killed them, but their bodies were not found for five weeks.

Investigators were at the home several times but never went inside.

"We had thought that possibly Mann and Capobianco had just left the house and went elsewhere, but we were there several times and, to be quite honest with you, probably should've been discovered, and that's something we're working through here internally,” said Capt. Steve Scharschmidt, with the Parma Heights Police Department.

Knuff had served more than 15 years in prison for robbery.

He's in jail on $50 million bond.