Details emerge on how Texas gunman obtained weapon

The 36-year-old gunman who killed seven people and wounded 22 others in West Texas on Saturday purchased his AR-style rifle from a private seller, federal law enforcement sources confirmed to CBS News. The purchase allowed the gunman to evade a federal background check. 

The investigation into who sold the weapon is ongoing. Authorities said the gunman was killed by officers outside a busy movie theater in Odessa. It was at least the 38th mass killing this year.

Online court records show the gunman, identified as Seth Aaron Ator, was arrested in 2001 for a misdemeanor offense that would not have prevented him from legally purchasing firearms in Texas.

FBI special agent Christopher Combs said Ator “was on a long spiral down” before the shooting on the day he was fired from his trucking job. He went to work that day “in trouble,” Combs said. He said the place where the gunman lived was “a strange residence” and that the condition reflected “what his mental state was going into this.”

Jeff Pegues contributed to this report.