An ex-cop's missing wife once confessed to her pastor that her husband admitted killing his third wife, the pastor told FOX News' Greta Van Susteren in an interview that aired Monday night.

Former Westbrook Christian Church pastor Neil Schori told "On the Record" that he was "reeling inside" after his conversation with Stacy Peterson over coffee in August.

"He killed Kathleen (Savio)," Stacy Peterson had said, according to Schori.

Savio's body was found in her bathtub in 2004 and her death initially was ruled an accidental drowning. After Stacy Peterson vanished in October, prosecutors opened another investigation into the Savio case and have said it appears her death was a homicide staged to look like an accident.

Stacy Peterson offered enough detail to be credible, said Schori, who declined to discuss those details in the interview.

"But it was very clear that this was not just speculation," he said. "She was not jumping to conclusions."

Joel Brodsky, Peterson's attorney, told "On the Record" that he would love to cross-examine Schori because "there are a lot of problems with his story."

Schori said he thought Stacy Peterson never shared the information about Savio with police. Asked why Stacy Peterson chose to stay with her husband after learning about his former wife's death, Schori said, "My guess would be out of fear."

Although he has not been arrested or charged, Drew Peterson, 53, has been named a suspect in Stacy Peterson's disappearance by Illinois State Police, who have labeled the case a possible homicide.

Stacy Peterson was last seen Oct. 28 and reported missing by her family the next day. Drew Peterson, a longtime member of the Bolingbrook Police Department until he quit after his wife went missing, has denied any involvement in her disappearance. He has said he believes his wife left him for another man and is alive.

Last month, the Westbrook Christian Church's pastor of spiritual formation told The Associated Press that Stacy Peterson requested an August meeting with a member of their pastoral staff when the church made a routine call to see why she and Drew Peterson had not attended services in recent months.

The Associated Press contributed to this report.