One Goh, the former Oikos University student accused of killing seven people at the college's campus in Oakland, Calif., told authorities he was upset with being expelled and had sought out a female college official, the city's police chief said Tuesday.
Goh "then went through the entire building systematically and randomly shooting victims," Oakland Police Chief Howard Jordan said at a news conference.
"We do know that he was upset at administrators at the school. We do know that he was upset with several students here because of the way he was treated when he was enrolled here two months ago," Jordan said.
He said Goh, 43, had been teased. The South Korean national had been expelled, possibly for behavioral problems, according to Jordan.
"They disrespected him, laughed at him. They made fun of his lack of English speaking skills. It made him feel isolated compared to the other students," Jordan said.
Other reports indicated that Goh, who reportedly had been a nursing student, recently lost two family members and had debts.
In Monday's rampage -- the deadliest U.S. campus shooting since the 2007 Virginia Tech killings -- one witness said Goh told students: "Get in line and I'm going to kill you all."
Jordan said Goh first took a receptionist hostage and then went looking for a particular female administrator. He then took the receptionist into a classroom and, on realizing the administrator was not there, he shot the receptionist and lined students up against a wall.
Goh surrendered Monday afternoon at a grocery store several miles away from the scene.
Paul Singh, whose 19-year-old sister Devinder Kaur was shot in the arm during Monday's rampage, told Reuters that according to his sister, Goh was a former student who showed up to class for the first time in four months.
''Get in line and I'm going to kill you all,' is what he said this morning, my sister told me. They thought he was joking at first,'" Singh said.
Tashi Wangchuk, whose wife attended the school and witnessed the shooting, said he was told by police that the gunman first shot a woman at the front desk, then continued shooting randomly in classrooms.
Wangchuk said his wife was in her vocational nursing class when she heard gunshots. She locked the door and turned off the lights.
The gunman "banged on the door several times and started shooting outside and left," he said. Wangchuk said no one was hurt inside his wife's classroom, but that the gunman shot out the glass in the door. He said she did not know the man.
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