At the First United Presbyterian Church of Coudersport an elementary school teacher shot dead his ex-wife as she sat in the pew, the Associated Press reports.
Gregory Eldred, 52, is in custody, the BBC reports, for the alleged murder of Darlene Sitler, 53.
Church Pastor Evon Lloyd told police that Eldred "leveled a gun at the victim and shot," according to the criminal complaint.
CBS News reported eyewitnesses telling police they apprehended Eldred after the shooting.
Police Trooper Michael Knight told the local paper, Bradford Era, that Eldred, during church service, walked down the isle and fired two shots at Sitler.
Potter County Commissioner Susan Kefover said the shooting was "devastatingly tragic for the community," according to CBS News.
He added, "It's hard to even comprehend it. You just feel this tremendous grief and you're trying to process what happened."
Sitler had been a music teacher at the Northern Potter Children's School for 30 years.