The man police believe walked into a Washington mall and murdered five people with a rifle has been arrested. From CNN:

Arcan Cetin, 20, was taken into custody Saturday night after a nearly 24-hour manhunt, authorities said…

Authorities arrested Cetin as he walked down the street near his home in Oak Harbor, Washington.

When officers confronted him, he did not run, said Lt. Mike Hawley of the Island County Sheriff’s Office. Instead, he froze and complied, Hawley said. Cetin was not armed at the time of his arrest.

“He said nothing,” Hawley said. “Just kind of zombie-like.”

So far police haven’t said anything about his motive but it seems there are three main possibilities. First, this could have been some kind of personal attack aimed at someone Cetin knew. At a press conference (video below) police said they were not aware of any connection between Cetin and any of the victims; however, they also hadn’t completely ruled it out. So for the time being this is still an outside possibility.

Second, this could be someone with mental problems or someone who wanted to carry out a random shooting for reasons of their own. The Seattle Times reports Cetin has a criminal record:

Skagit County court records show Cetin has a criminal record that included three domestic-violence assault charges in both Burlington and Island County, with the victim identified as Cetin’s stepfather. He also was arrested for drunken driving.

And KIRO 7 reports Cetin underwent a mental health evaluation and some mandatory counseling:

As part of that misdemeanor case, Cetin was ordered to undergo a mental health evaluation in August 2015. The evaluation was completed as of March 2016, according to court records…

In May, a judge approved deferred prosecution in that assault case – meaning Cetin was not convicted – and he was ordered not to have alcohol or drugs as part of the deferment.

As of Aug. 25, 2016, Cetin was in compliance with weekly sessions for mental health counseling. He complied with the alcohol assessment, according to court records, and he had a deferred prosecution review for the case scheduled for 2018.

So maybe this is someone with a mental health problem which eventually led to this mass shooting.

Third, this could be another “lone wolf” terrorist attack inspired by ISIS. Authorities have said that they haven’t ruled out terrorism as a possible motive. Cetin is originally from Turkey though he is now a “legal permanent resident” in the U.S. Authorities haven’t said when he arrived in the U.S. or made any indication of a connection to terrorism. Obviously that could change quickly once they talk to him.

Finally, the Seattle Times notes that some of the victims have been identified. The youngest victim was a 16-year-old girl who had survived cancer:

Sarai Lara was the youngest of the victims, at 16. The Mount Vernon High School sophomore had survived cancer as a young girl, and was a happy, responsible, driven student, her mother said Saturday evening.

Evangelina Lara said she was shopping at the mall with Sarai and her younger sister, but they split up to different stores. Sarai went to Macy’s looking for pants, her mother said through a translator. News of the shooting spread through the mall, and Lara tried to get to her daughter but was blocked from Macy’s.

Cetin has been charged with five counts of first-degree murder.

*Correction: Earlier I had written Cetin was a U.S. Citizen. He’s not. He’s a “legal permanent resident” according to Lt. Chris Cammock.