Police worked into the early morning hours Thursday, combing through the apartment of a man accused in the fatal shooting of a prayer leader at World Changers Church International in College Park, Georgia.

Floyd Palmer, 52, was arrested Wednesday afternoon and charged with the fatal shooting of 39-year-old Greg McDowell. It was the second time Palmer had been charged with shooting a man in a church; he pleaded guilty to shooting a man a decade ago in Baltimore and was committed to a mental health facility there.

Police searched Palmer’s apartment at the Reserve at Garden Lake apartment complex in Riverdale Wednesday night and Thursday morning. They removed several items from the apartment, but it was not immediately clear what.

Resident Hoover Sirmans told the Atlanta Journal-Constitution he arrived home from his job as an EMT in Coweta County around 11 p.m. Wednesday to find the complex locked down by police. He said he went to a resident’s house to sleep and was able to go back home Thursday morning.

Sirmans said he knew Palmer only slightly, “just a hey-how-ya-doing basis … He seemed like a regular old guy.”

When he found out Palmer had been arrested in connection with the shooting, he said, “‘Wow’ is the only word I could say.”

Palmer calmly walked into a prayer service Wednesday morning at the College Park megachurch founded by the Rev. Creflo Dollar and opened fire as 20 to 25 people watched in horror. McDowell fell mortally wounded and Palmer, a former church employee, “left just as calmly” as he entered, Fulton County police spokeswoman Cpl. Kay Lester said.