Rem Houser said he was shocked by his brother John's alleged actions. Police say John Houser, 59, opened fire inside a movie theater in Lafayette, Louisiana, on Thursday, before he died from a self-inflicted gunshot wound.
"I never thought anything like this would happen," Rem Houser told ABC affiliate WSB-TV in Atlanta. "We're just in shock about the whole thing."
Houser declined to talk about his brother's past. Court documents show John Houser allegedly threatened his family and was involuntarily committed to a hospital in Georgia seven years ago.
Rem Houser offered thoughts and prayers to the families of the victims.
"We just pray for them and we're thinking about them," he said.
Authorities were still trying to piece together why Houser, who they described as a "drifter" living at a motel, opened fire.
Police said he was "intent on shooting and escaping" and kept wigs and disguises in a nearby motel room. The handgun he used in the shooting was legally purchased at a pawn shop in Phenix City, Alabama, last year, Lafayette Police Chief Jim Craft said Friday.
The domestic violence complaint was never prosecuted.
Houser allegedly threatened his family, who took out a temporary protective order against him in April 2008, according to court filings. The protective order was lifted the next month.
Houser and his wife were married and lived together from 1983 to 2012, according to court filings obtained by ABC News. The couple separated in December 2012 and she then filed for divorce in March 2015, the documents show. The divorce is not yet final.
His estranged wife and her family have declined comment on the shooting.