Messages left with friends and relatives of Ybarra via social media were not immediately returned.
The Seattle Times reported that the suspect’s father, Ambrose Ybarra, said he didn’t know anything about the shooting.
“We just hope he’s safe,” he told the newspaper. “It’s upsetting to have these accusations thrown around. We’re in emergency mode. We are trying to stay calm.”
The paper said Zack McKinley described himself as one of Ybarra’s closest friends and said he was “super happy and friendly.”
McKinley said the attack was puzzling because Ybarra was happy to have just started a job bagging groceries at a store.
He said Ybarra didn’t do drugs or drink alcohol and spent time writing. Ybarra could get emotionally low, but McKinley said he had a good group of friends and never saw him depressed.