Clackamas County Sheriff Craig Roberts Wednesday said the gunman was Jacob Tyler Roberts, 22, and confirmed he died of a self-inflicted gunshot wound. But the sheriff said he was unable to give the man's motive, or say how many shots he fired.
The dead were identified as Cindy Ann Yuille, 54, and Steven Mathew Forsyth, 45, both of suburban Portland. Kristina Shevchenko, 15, was seriously wounded and was being treated at a Portland hospital.
Roberts said the suspect was carrying an AR-15 semi-automatic assault rifle, stolen from a friend, and wore an ammunition vest and a hockey mask.
The sheriff said investigators "cannot understand the motive ... except there was no apparent connection between the suspect and his victims." Roberts said he would not release the results of a search warrant executed at the shooter's home.
"Everyone (of the officers responding) did an amazing job," Roberts said, and police had "practiced for just this type of situation" at the mall earlier this year.
"This was a heartbreaking tragedy by any standard," the sheriff said. " ... On the other hand we all need to be thankful that this incident wasn't much worse."
He credited three factors for many more victims not being shot: The shooter's weapon jammed in the food court, though he managed to get it working again; a "large number of police arrived very rapidly," and "10,000 people in the mall kept their head," getting out and helping others get out calmly.
The gunman swept through the Clackamas Town Center Tuesday afternoon, firing away as he moved to the food court and other public areas.
Roberts told ABC News, "I believe, at least from the information that's been provided to me at this point in time, it really was a killing of total strangers. To my knowledge at this point in time he was really trying, I think, to kill as many people as possible."