The Rev. William Schooler turned over Sunday service at his Ohio church to the choir director and headed to his office.

Then, as the choir sang, Schooler was shot and killed, the Dayton Daily News reported.

“We heard pow, pow,” St. Peter’s Missionary Baptist Church member Beulah Booker-Robertson told the newspaper. “The usher at the door said ‘everybody get down, everybody get out.'”

On Sunday, police arrested Schooler’s brother, Daniel Gregory Schooler, on murder charges. He is expected to be formally charged Tuesday and arraigned Wednesday, Dayton Police Sgt. Richard Blommel told The Post.

Jail records do not list attorney information for Schooler.

“It’s a domestic-related incident,” Blommel said.

Reports paint a chaotic scene at St. Peter’s Missionary Baptist Church in Dayton. About 20 people were in the congregation during the shooting, and William Schooler was pronounced dead at the scene, WDTN reported.

“I just got everybody out of the church and we just kept hearing shooting and shooting,” parishioner Alberta Blayth told the Dayton Daily News.

A parishioner who called 911 told the emergency dispatcher, “We were still having church services when he started shooting,” according to audio obtained by WDTN-TV.

The pastor, 70, was shot multiple times, police told the newspaper.

“I can’t believe it,” church member Vonette McGraw told the station. “I can’t believe that my pastor is gone.”

William Schooler once served on the Dayton Public Schools Board of Education and was president of the Dayton Baptist Pastors and Ministers Union of Greater Dayton, according to WDTN.

Joyce Napier, niece of William and Daniel Schooler, told the Dayton newspaper that Daniel Schooler had struggled with mental illness. Her family, she said, is in pain.

“We stick together. And we pray,” she told the newspaper. “And don’t turn on each other … because he has daughters, the other one has daughters. And we loved them both, so we have to stick together. That’s all we know, that’s all we have.”

[This story has been updated.]