OAKLAND, Calif. — Before embarking on a shooting rampage at a religious college that left seven people dead, the gunman, a former nursing student, moved deliberately through a school building, lining students up against a wall before gunning them down execution-style and hunting others down after they had taken cover under their desks, the authorities said Tuesday.
Of the seven people who died, six were women. Three other people were wounded.
One L. Goh, a 43-year-old Korean immigrant who was arrested after the attack, has admitted to the shooting at Oikos University, a small college in East Oakland, the authorities said.
The police said Tuesday that Mr. Goh might have been prompted to kill because people at the college had made fun of the way he spoke English. The authorities cautioned, however, that a clear motive had not yet been established.
“He was very upset,” said Officer Johnna Watson, a spokeswoman for the Oakland Police Department. “He had been being teased by his classmates because his English was not very good, and that angered him. He says that made him very mad.”
The police described Mr. Goh, who was not enrolled in the college this semester, as being “cooperative” with investigators, and said he had provided a chilling account of how he armed himself with a semi-automatic pistol and systematically sought to shoot as many people as possible — including those who sought to flee.
Officer Watson said Mr. Goh had told investigators that on Monday at about 10:30 a.m. “he went to the college specifically looking for a female administrator,” but that the administrator was not there.
The police said it was unclear why Mr. Goh had been looking for the administrator, whose name has not been released by the authorities.
After failing to find the woman, the police said, Mr. Goh took a hostage and forced her into a classroom where he ordered students to line up against a wall. He shot them one by one.
Next, Mr. Goh fatally shot his female hostage and then moved “through the classroom into other areas of the building where he additionally shot other people who were trying to hide under desks or trying to hide in closets,” Officer Watson said.
Mr. Goh tried to shoot his way past a locked door that led into an adjacent classroom, but was unsuccessful, the police said. He then fled in a car stolen from a student before turning himself in to an employee at a Safeway grocery in Alameda, several miles from the college.
“He is upset and disgruntled,” Officer Watson said Tuesday. “He used to be a student at the college. He was no longer a student. We don’t know all the details of his motive. That is still being worked out.”
She said the gun used in the shootings had not yet been recovered. “The suspect has said that he discarded it,” she said. “We are actively searching for it. We have a general location.”
The gun was purchased legally in California in 2012, she said.
Oikos University is a Christian college affiliated with a Korean-American church, Praise to God Korean Church, and situated in a commercial and industrial area near Oakland International Airport, where there are many Korean-American businesses.
Howard Jordan, Oakland’s police chief, said at a news conference on Monday night that Mr. Goh had acted alone.
“Today’s unprecedented tragedy was shocking and senseless,” Chief Jordan said.
Jean Quan, the Oakland mayor, appearing at the news conference with the police and a representative of the Korean consulate general, said most of the victims were Korean. Chief Jordan said Mr. Goh was a naturalized American citizen from Korea.
“This is the kind of situation where we need to pull together to support the Korean community in particular,” Mayor Quan said. “I hope we will put our arms around these people and this community.”
The police got the first word of the shootings at 10:33 a.m. and were at the university in less than 10 minutes, Chief Jordan said. He described the scene as “very chaotic” and said the killer was believed to have been inside a classroom when he started shooting.
Tashi Wangchuk, 38, a videographer from Richmond, Calif., said he had gone to the college after getting a call from his wife, Dechen, a nursing student at Oikos.
“My wife called and said, in a hushed voice, ‘Call 911. There’s a shooting going on in here,’ “ he said. “She told me someone came in with a gun and started shooting randomly.”
Mr. Wangchuk’s wife, who was crouching inside a classroom with other students, said the gunman had shot through the door of the classroom before leaving, her husband said. On Monday afternoon, she was still inside the university as the police locked down the area around the small college.
Relatives clustered outside the college, along a grassy median, trying to get word from the authorities about when their children or spouses would be released. What appeared to be four bodies were laid out, under sheets, on the median. The wounded had been taken away in ambulances.
“It’s just a sad day in my city whenever there’s a loss of life,” said Larry Reid, who is the president of the Oakland City Council and represents the district where the shooting occurred. “There are just too many guns in the hands of people who are not afraid to use them.”
Gov. Jerry Brown, a former Oakland mayor, said in a statement: “The tragic loss of life at Oikos University today is shocking and sad. Our thoughts and prayers go out to the victims, their families and friends, and the entire community affected by this senseless act of violence.”
According to the college’s Web site, “Oikos University was launched to provide highest standard education with Christian value and inspiration.” Oikos offers courses in music, nursing, English, Bible studies and other subjects. It caters largely to Korean and Korean-American students.
Deborah Lee, 25, who studies English as a second language at the university, said she was inside a classroom Monday morning. “I heard some gunshots and women screaming: ‘Somebody has a gun — run!’ “ Ms. Lee said.
She said she had heard five or six gunshots. “My teacher yelled, ‘Run, run,’ and we all ran outside,” she said.
Ms. Lee said she had not seen the gunman. “I heard a pop, pop, pop sound and then girls screaming,” she said. Ms. Lee said she believed the shooting had occurred in the same building as her classroom.
She was frightened, she said, but added, “I’m a Christian, and I believe God protects me.”
Chief Jordan said the department would not release names of victims until next of kin had been notified and further investigation had been conducted.