Two years later, officers responded again - this time finding him lying in the middle of the street in front of his suburban Mountlake Terrace home, ranting drunkenly for a SWAT team "to get him and make him famous."
The rage and thirst for notoriety may have got the better of him Thursday, when police say he stormed into a sciences and engineering building on the leafy campus of Seattle Pacific University, armed with a shotgun and more than 50 shells.
He fatally shot a 19-year-old freshman and wounded two other young people before his plan to kill as many people as possible - and himself - was thwarted by a student building monitor who pepper-sprayed and tackled him as he reloaded, officials said.
A King County Superior Court judge ordered Ybarra, 26, held without bail Friday. His attorney, public defender Ramona Brandes, said he was on suicide watch at the jail.
"He is cognizant of the suffering of the victims and their families and the entire Seattle Pacific community," she said. "He is sorry."
In both of the earlier contacts with police, officers committed Ybarra involuntarily to Swedish Hospital in Edmonds for mental evaluations. Brandes said he has a long history of mental health problems for which he had been treated and medicated.
"We are so very shocked and sad over yesterday's shootings at SPU," Ybarra's family said in a statement. "We are crushed at the amount of pain caused to so many people. To the victims and their families, our prayers are with you."
At the time of the 2010 commitment, Ybarra worked at the Kenmore Shooting Range north of Seattle. From 2003 to about three and a half years ago, he worked as a 'trapper' keeping score on practice shoots, according to range president John Conderman, who said he did not know Ybarra personally but recognized his picture in news accounts.
"This is so disappointing," Conderman said. "We spend all of our energy trying to teach young people about responsible gun use."
Tyson Winter, who worked at a now-shuttered sandwich shop in Edmonds in the middle of last decade, said Ybarra frequently came by and attempted to befriend the high-school age workers, inviting them to go drinking and shooting. Ybarra began leaving Winter rambling phone messages about guns, and then asked Winter why he didn't call back, Winter said.
Eventually, Ybarra was asked to stay away from the shop.
"He was socially awkward but he wasn't shy at all. He wanted to befriend us," Winter said.
It remained unclear why the private Christian university was targeted. Ybarra wasn't a student there, police said.
Praise poured in for Jon Meis, the 22-year-old building monitor who subdued the gunman.
"I'm proud of the selfless actions that my roommate, Jon Meis, showed today taking down the shooter," fellow student Matt Garcia wrote on Twitter. "He is a hero."
Meis, a dean's list electrical engineering student, was emotionally anguished but not injured in the shooting, Harborview Medical Center spokeswoman Susan Gregg said Friday. He was treated there and released.
Roman Kukhotskiy, 22, who was in the building when the violence broke out, said: "I was amazed that he was willing to risk all that for us. If Jon didn't stop him, what's to say? I could have been the next victim."
He said Meis is getting married this summer and has accepted a job with Boeing, where he has interned in previous years.
The leafy campus of the private, Christian university about 10 minutes north of downtown Seattle was quiet the morning after the shooting, with a service held at midday. People stopped by a makeshift memorial near Otto Miller Hall to pay their respects.
Seattle Mayor Ed Murray identified the student killed as Paul Lee, a "Korean-American student with a bright future."
"What a waste," said Susan Savage, of Portland, Oregon, who said Lee's friends gathered at her house Thursday night to remember him.
"This guy, with his personality, he would have soared. He would have accomplished. He was one of the good guys. It's just a loss. He would have added to the quality of our world, and now we'll never know," she said.
The victims included a seriously wounded 19-year-old woman who remained in intensive care after a five-hour surgery, as well as a 24-year-old man who was discharged from the hospital Friday, Gregg said.
Meis, who graduated from Seattle Christian Schools in SeaTac, kept a low profile the day after the shooting. An outgoing voice message at a phone listing for his parents' home in Renton said: "We ask that you please respect our privacy during this time while we recover." It solicited prayers for students and the family of the man killed.
Salomon Meza Tapia, a friend who serves with Meis on the board of a student engineers group, described him as a hardworking student who is "always super chill."
"I am not surprised he was cool and collected enough to take action," he wrote in an email to the AP. "I was in the building, and I can say he definitely saved our lives. I am thankful to be alive and thank God for Jon Meis' courage and actions."