Authorities say he used a 12-gauge shotgun and traveled 25 miles to kill three people, then himself, Tuesday morning.
But to his computer repair teacher at Saddleback College, Ali Syed was just a normal, quiet student.
"He didn't give any reason for alarm or concern," Eugene Evancoe told the Lariat, the campus newspaper.
Syed was enrolled in one Wednesday morning class on computer maintenance and repair this semester, said law enforcement and the Lariat.
When Evancoe broke the news to Syed's classmates Wednesday morning, they responded with silence, he said.
"I don't think anyone knew him," Evancoe told the Lariat. "(The class) didn't really show a lot of reaction at all."
He regularly attended, showed interest in the subject and got along well with other students, Evancoe said. He didn't excel in class, but didn't do poorly either. Evancoe described him as "probably a B student—an A-B student."
And how was he to talk to?
"He didn’t talk a lot, but when he did he was polite and kind and nice," Evancoe said.