Oregon mall shooter Jacob Tyler Roberts identified by police; he used a stolen rifle

PORTLAND, Ore. - The gunman who killed two people before turning the gun on himself in an Oregon mall was identified less than a day after his rampage.

Clackamas County Sheriff Craig Roberts says that Jacob Tyler Roberts, 22, had armed himself with a AR-15 semiautomatic rifle and had several fully loaded magazines. The weapon was stolen from someone he knew.

Roberts says the rifle jammed during the 22-year-old's attack, but he managed to get it working again.

The Sheriff says authorities don't yet have a motive.

In addition to the deaths, one person was injured in the shooting. She was identified as Kristina Shevchenko.

Dr. Lascio Kiraly of Oregon Health and Science described her injuries as "serious" wounds caused by a high-velocity weapon. She had a collapsed lung and liver injury, he said.

Shevchenko underwent a successful operation and remains in serious condition. 

Nadia Telguz, who said she was a friend of Shevchenko's, told ABC News affiliate KATU-TV in Portland that the woman was expected to recover.

"My friend's sister got shot," Teleguz told KATU. "She's on her way to (Oregon Health and Science University hospital). They're saying she got shot in her side and so it's not life-threatening, so she'll be OK."

More than 10,000 shoppers were at the mall during the day, police said. Roberts said that officers responded to the scene of the shooting within minutes, and four SWAT teams swept the 1.4 million-square-foot building searching for the shooter. He was eventually found dead, an apparent suicide.

The Sheriff said more than 100 law enforcement officers responded to the shooting, and at least four local agencies were working on the investigation, including the FBI and Bureau of Alcohol, Tobacco and Firearms, which is working to trace the shooter's weapon.

"For all of us, the mall is supposed to be a place where we can take our families, especially during the holiday season," the Sheriff said. "Things like this are not supposed to happen."

A law enforcement official has told The Associated Press Jacob Roberts did not have a criminal record. The official spoke on condition of anonymity because he was not authorized to discuss details of an ongoing criminal investigation.

Two people were killed, and another was wounded.