California cops gunned down an armed man inside a Catholic church between scheduled Sunday Masses, according to cops and a new report.

Officers were responding to an unrelated call across the street from Immaculate Heart of Mary in Santa Ana when a parishioner flagged one of them down to report a man with a gun inside, police said in a statement.

The cop immediately went inside and found the gunman at the altar with the weapon in his hand, Santa Ana Police Cpl. Anthony Bertagna said, according to The Orange County Register.

The officer fired at the gunman, striking him, but he managed to stumble his way outside — still carrying the weapon — before collapsing about 100 feet outside the church, the paper reported.

He was pronounced dead on scene.

About 10 to 15 people, believed to be choir members, were inside the church at the time.

But cops do not believe the man was planning a “mass casualty shooting” targeting the parish or Catholicism in general.

He appeared distraught and possibly suicidal, Police Chief David Valentin told the Register.

“We understand he was distraught over a relationship,” Bertagna said. “We’re not sure if that’s why he was here.”

Authorities initially received reports of a possible second gunman and shots fired — but officers did not locate any other suspects or evidence of another shooting.