OAK HARBOR, Wash. — The 20-year-old man suspected of killing five people with a rifle at a Macy’s makeup counter had a string of run-ins with the law in recent years, including charges he assaulted his stepfather, and was described by a neighbor as so “creepy, rude and obnoxious” that she kept a Taser by her front door.

As investigators tried to piece together information on Arcan Cetin, who was arrested Saturday evening after a nearly 24-hour manhunt, a picture emerged of a troubled young man. Court records show more than a half-dozen criminal cases in Island County alone since 2013.

Authorities said the gunman in the attack at the Cascade Mall in Burlington opened fire in the department store’s cosmetics department Friday night, killing a man and four females ranging from a teenager to a senior citizen. The killer then fled.

Cetin said nothing and appeared “zombie-like” when he was taken into custody on a sidewalk outside his apartment complex some 30 miles away in Oak Harbor by a sheriff’s officer who recognized him as the suspect in the rampage, authorities said.

Cetin immigrated to the U.S. from Turkey and is a legal permanent resident, officials said.

As the surrounding area absorbed news of the arrest, critical questions remained, including the gunman’s motive. The FBI said early Saturday that there was no indication the shooting was terrorism, but local authorities said later in the day that they were ruling nothing out.

On Sept. 17, a 20-year-old man stabbed 10 people at a Minnesota mall before being shot to death by an off-duty police officer. Authorities said they are investigating the attack by Dahir Ahmed Adan as a possible act of terrorism.

On Sunday, investigators searched Cetin’s vehicle and the apartment complex and were seen carrying boxes from a rear, upstairs unit. The four-unit building was surrounded with yellow police tape. Detectives would not say what they found.

Amber Cathey, 21, lived in an apartment next to Cetin for the past three months and said she was so frightened by him that she complained to apartment management and kept a stun gun handy. Cathey said she blocked him on Snapchat after he sent her a photo of his crotch.

“He was really creepy, rude and obnoxious,” Cathey said. She said she would try to avoid him by walking the long way around to her apartment if she saw his car in the parking lot. The two were in high school together as well, and Cathey said he acted the same way then.