Nervous parents rushed to the school just before noon Wednesday after getting word that police were looking for a man with a gun, and their kids were being escorted off campus.
The incident took place in the Maxwell Park neighborhood at Fleming and Monticello avenues, right by Interstate 580 in east Oakland.
It could have ended much worse than it did. Oakland police used restraint in dealing with an armed man. And the staff of a school kept cool heads as well.
It was anything but a pleasant outside lunch for the students and staff of Maxwell Park International Academy, not with a gunman just up the street.
Police have not said if the gun was loaded.
Anxious parents converged after hearing of the emergency.
"I mean it makes no sense for them to be sitting in the open when they're saying there is a gunman saying he is willing to shoot anybody," parent Danyell Thomas said.
She wasn't the only mother to be upset.
"I have no idea, I don't know what happened," the suspect's mother, Vanndy Leng, said.
Leng's 21-year-old son Peng was the potential shooter. Witnesses say that while working on his car, he pulled a shotgun from inside, and laid it on the street. The crisis escalated when somebody called police.
"He was just racking it, racking the gun," witness Gregory McCowan said.
But school staff considered it to be a threat. First, they sheltered 250 kids in place. Once police had the suspect surrounded, they evacuated classes out a back door, to a park half a block away.
"There will always be a little confusion when parents see helicopters and they see a mass number of police cars, they're going to be frightened, any parent would, but overall I think it was handled competently," Oakland Unified School District spokesperson Troy Flint said.
Police took Leng into custody with no shots being fired. It's all fairly baffling to those who know him.
"Basically, he's just a good kid," McCowan said.
At the least, one with apparently bad judgment about firearms.
It was a worrisome experience for kids, and especially parents.
The Oakland Unified School District will send a formal explanation of what happened in a letter to parents. It will include an offer for counseling, if necessary.
This won't be the first letter parents have seen. Maxwell Park International Academy was already a tender subject. The district plans to close it at the end of this year.