The Washington State man accused of killing three people at a party on Friday night with an AR-15 read the rifle's instruction manual just moments before opening fire, court records show.
Allen Ivanov, 19, told detectives he bought the semi-automatic rifle a week ago for target practice and had even scheduled a safety class for August, according to a probable cause form released Monday.
But Ivanov instead brought the gun with him to a party that his ex-girlfriend was attending in Mukilteo, a Seattle suburb, investigators say.
In an interview with detectives, the document reads, Ivanov said he hoped to get back together with the girl, identified as A.B.
But after seeing her with another man at the party, he returned to his car, fetched the rifle, read the instructions and loaded its magazine. He then brought it with him to the party, the document says.
As Ivanov crept around the outside of the house, a male party goer discovered him, it states.
"The male said, 'No, no, no,'" the document says. "Ivanov stated that he was 'scared,' he flipped the [gun's] selector switch to fire and shot the male."
The document adds: "He stated that at that point it was too late to turn back, and once had pulled the trigger his adrenaline kicked in."
He found A.B. and shot her twice, killing her, then gunned down another man running toward the party, the document says. From the master bedroom balcony, he fired at two more people in the driveway, then climbed to the roof and discovered that he'd emptied his rifle.
"Ivanov stated that once the magazine was empty, he returned to his car and drove away," the document says.
Ivanov, who is being held without bail at the Snohomish County Jail, was charged with two counts of first-degree murder and one count of first-degree aggravated murder. It wasn't immediately clear if he had a lawyer.