During this time, Gerald Hume reportedly said his mother was on a trip or he simply refused to answer the door.
Police obtained a search warrant Nov. 13 after failing to locate Janet Hume or make contact with her son.
Gerald Hume, who was subdued using bean bag projectiles, pointed a 9 mm handgun at two police officers during his arrest, Porter reported.
Oklahoma City police dealt with Gerald Hume four separate times before last week's arrest.
Oklahoma City police Capt. Dexter Nelson said police have been called to the residence four times over the past six years, most recently in April 2011.
He said all the incidents involved “some aspect of Mr. Hume's mental health.”
In August 2009, police dealt with Gerald Hume after an incident at his mother's home.
“Gerald was involved in an incident in which he boarded up the windows of the residence, and shot at vehicles as they drove by,” Detective Jacobson wrote in the search warrant affidavit.
Nelson said police cannot release reports related to the prior incidents because they relate to Gerald Hume's mental health.
He also was arrested in 2007 on a complaint of leaving the scene of an accident, a misdemeanor.
As for how Gerald Hume was able to get his hands on so many guns, Nelson said he wasn't sure how it happened.
“That is something I don't know … but I would assume we will look into that,” he said. “But there are a lot of ways people with mental issues can get guns … there's just so many loopholes.”
A relative of the victim told police he had removed several rifles from the house because of Gerald Hume's mental condition, according to the search warrant affidavit.
Detectives reported a family friend said “Janet Hume told her that Gerald had recently bought several guns,” according to the search warrant affidavit.
Nelson said anybody — regardless of criminal history or mental stability — can purchase firearms at gun shows or from ordinary “citizens.”
“You can sell those guns to anybody you want to, as a citizen,” he said. “You have no obligation to check that person out.”
Even if Gerald Hume had attempted to buy a gun from an authorized dealer, Nelson said, he could've possibly succeeded. “The state of Oklahoma doesn't transfer information to the national mental health database … a lot of states don't,” Nelson said. “It's not regulated that they do it.”