A man with an extensive criminal record is accused of stabbing nine people, including six children, at a 3-year-old’s birthday party, authorities said.

Timmy Kinner showed up late Saturday at the Boise complex, which houses many resettled refugee families. Kinner, who is not a refugee, targeted the party that was held a few doors down from the apartment where he had stayed for a short time, police said.

All nine victims were refugees from overseas.

“These are victims who in their past homes have fled violence from Syria, Iraq and Ethiopia,” Police Chief William Bones said Sunday, according to The Idaho Statesman. “The crime scene, the faces of the parents struggling, the tears coming down their faces, the faces of the children in the hospital beds, will be something that I will carry with me for the rest of my life. And so will every first responder that was there last night.”

The victims included the 3-year-old birthday girl and five other children ages 4 to 12. Three adults who came to their defense were also hurt. Some were gravely wounded, Bones said.

A resident of the complex had recently met Kinner, who was new to the area and needed a place to stay, Bones said.

"I believe her perception was, 'Here's a helping hand I can give in return for a helping hand I have been given,'" Bones said.

The resident asked Kinner to leave Friday when his behavior became a problem, and he did so peacefully, Bones said. The police chief did not elaborate on his behavior. The woman was not among the victims.

Esrom Habte, 12, and Fathi Mahamoud, 11, were playing in the grass behind their apartment when the attack began. They saw the suspect chasing people.

"We saw him saying, like, bad words and stabbing a kid and a grown-up and really hard and a lot of times," Esrom said.

The two ran into an apartment and hid in a closet with other children until police told them it was safe to come out, he said.

Some of the stabbing victims were their friends, Fathi said.

Kinner, 30, was arrested near the scene and charged with aggravated battery and of injury to a child. Investigators recovered the knife he was believed to have used in a nearby canal, Bones said.

The attack resulted in the most victims in a single incident in Boise Police Department history, the police chief said.

"The crime scene, the faces of the parents struggling, the tears coming down their faces, the faces of the children in their hospital beds will be something that I carry with me for the rest of my life, as will every first responder that night," he said.

The apartment complex is just off of one of Boise's busier streets, separated from the traffic by one of the many irrigation canals that run through the city. On Sunday, colorful bouquets had been placed just outside crime-scene tape.

Residents of the apartments and the rest of the community were "reeling" from the violence, Bones said, and will need long-term community support.

"This isn't something that gets over in the days or weeks that follow. ... The level of the some of the injuries will be life-altering in a very negative way," Bones said.

The Associated Press contributed to this report