Students at Oikos University recognized the man who entered their classroom Monday morning as a former nursing student who hadn’t been around for a few months.

Then he ordered everyone to get up against a wall, and he drew a handgun.

“The people started running, and he started shooting,” said Gurpreet Sahota, who relayed an account from his sister-in-law, nursing student Dawinder Kaur, 19.

Seven people died, and three more were wounded in the shooting at the small Christian university, the Bay Area’s worst mass killing in almost 20 years.

Police said the victims are six women and one man ranging in age from their 20s to 40s. The man was identified as Tshering Rinzing Bhutia, 38, of San Francisco, killed when the gunman stole his car outside the school Monday morning. Two of the women killed were 21-year-old student Lydia Sim and 24-year-old Kathleen Ping, authorities confirmed.

Police Chief Howard Jordan on Monday evening confirmed the arrest of 43-year-old One Goh, of Oakland, a Korean native and naturalized U.S. citizen. Not much was immediately known about One, but Jordan said he had no known previous criminal record. Officers believe he acted alone.

Following the shooting, One drove Bhutia’s car about five miles from the school to an Alameda supermarket, where he announced he had shot people and should be arrested. A security guard detained him until police arrived; a shopper who witnessed a man being handcuffed said he seemed very sedate.

The scene was chaotic back at Oikos, which occupies a small building on Edgewater Drive just north of Hegenberger Road in a business park between Interstate 880 and Oakland International Airport. The scene there was slaughter.

Kaur, 19, a U.S. Army Reservist from Santa Clara, told relatives the gunman had been a student in her class but had been absent for months before reappearing Monday morning. Some panicked when he drew a gun and began firing; she was shot in the arm as she helped a friend who had fallen on the classroom’s floor. She then ran outside and called her brother, Paul Singh.

“She told me that a guy went crazy, and she got shot,” Singh said. “She was running. She was crying; she was bleeding. It was wrong.”

Police received a 911 call at 10:33 a.m. Art Richards, of Oakland, said he arrived at the school right around that time to pick up a friend who’s a nursing student there.

Shocking, senseless

Richards said he saw a young woman wearing blue scrubs — possibly Kaur — emerge from bushes near the building, with blood running down her right arm from a wound near her elbow. She told him the gunman had fired point-blank at a man’s chest, and she had been grazed by a bullet before she fled the building. “She was in shock, fearing for her life, she didn’t know what to say,” he said. “She had a piece of her arm gone, and that was just a graze from a bullet.”

Richards said the wounded woman also told him she had recognized the gunman as a former student who had “seemed kind of weird and that he wasn’t all there, and people would pick on him.”

Police arrived within a few minutes, swarming the building; soon other buildings nearby were locked down, and police and news helicopters hovered above. Richards said he saw officers tackle an Asian man near the school, but they quickly determined he wasn’t the suspect.

Officers advanced into the building, concerned the gunman might still be there and facing doors barricaded by terrified students. Some officers began smashing windows to get in; a police sergeant suffered a cut requiring hospitalization.

“About five or 10 minutes later, they drug out a body and placed it between two police cars. He was limp. They ran and grabbed a blanket, and we knew he was dead,” Richards said.

Police moved an armored vehicle in front of the school to provide cover as more than a dozen students and faculty — some of whom had been found cowering under desks — were evacuated by SWAT officers. Some of the wounded immediately were whisked away by ambulance while others were treated at the scene.

Authorities said most of those killed and wounded had been in a classroom near the school’s entrance, while one was shot in an administrative office. The gunman reportedly fired through another classroom’s locked door but didn’t hit anyone there.

Student Dechen Yangzom later was credited with having locked that other classroom’s door and turned off the lights as soon as she heard the first shots echoing from down the hall, very likely saving her own life and those of seven others inside.

Later, several bodies that had been removed from the school lay covered on the front lawn. Police said five people died at the scene; of five others who were taken to the hospital, two later died.

Kaur’s family, standing vigil as she was being treated at Alameda County Medical Center’s Highland Hospital, said they saw other victims as well: a man shot in the shoulder and a woman shot in her hand and back.

“It was a very bloody scene, and we have lots of evidence to collect,” Jordan said Monday evening. “This was an unprecedented tragedy. These deaths were shocking and senseless.”

About 35 people had been in or near the school at the time of the shooting, Jordan said, and the gunman apparently had fled before the first officer arrived. School officials quickly gave police the gunman’s name, photo and home address, to which officers were on their way when One turned himself in at the Alameda supermarket. Bhutia’s car was towed from there.

Jordan said Monday evening that police would not yet release 911 tapes, photos of One or names and photos of the victims. No one answered the door Monday at an apartment at Westlake Christian Terrace, a high-rise residential building on the 200 block of 28th Street where One’s father apparently lived. One’s last known address also showed him living in the complex, although his current residence was not immediately clear.

One’s brother, U.S. Army Sgt. Su Wan Ko, died in a traffic accident in Virginia in March 2011, while on special assignment from the George C. Marshall Center, an international security and defense studies institute in Garmisch, Germany. One Goh attended a memorial service in Virginia along with their father Young Nam Ko, 72, of Oakland. Their mother Oak Chul Kim, of Seoul, South Korea, attended as well but has since died, according to published reports. The suspect’s other brother, Su Kwon Ko, who lives in Virginia did not answer his phone for comment Monday.

Court records show several court judgments and tax liens against One dating back to 2006, when he lived in Virginia. He owed more than $23,000 in federal taxes at one point and thousands of dollars more to banks and apartment owners.

The most recent judgment, in December, was for $985 to Capital One Bank.

Police described Oikos as “a postsecondary vocational school with strong ties to the Korean community and Korean students.” A statement on the school’s website from founder and president Pastor Jongin Kim says it offers “the opportunity to obtain a Christian education that is based on solid Christian doctrine and ideology. Our main goal is to foster spiritual Christian leaders who abide by God’s intentions and to expand God’s nation through them.”

Gun control issue

Monday’s shooting occurred during Christianity’s holiest week.

Kim said Monday the shooter had previously been an Oikos nursing student but was no longer enrolled; he was unsure whether the shooter had been expelled or had dropped out voluntarily. Kim did not see the shooting but heard about 30 gunshots. “I stayed in my office,” he said, imitating the sound of rapid shots.

Kaur’s father, Balvir Singh, via translation by Sahota, said her family is “lucky she is alive. We are thankful that God saved her.” The gunman, he said, “should get the full consequences that he deserves for doing this to these people.”

Students panicked and ran from the building when the shooting started, said Nam Gong Kyun, a 52-year-old English student from Korea. Students and teachers throughout the building heard the shots, said Lucas Garcia, who has taught English at Oikos for three years. “We heard many gunshots,” he said. “Everybody was scared, obviously.”

Among those outside the school Sunday afternoon was Timothy Yi, pastor of Hayward Korean Baptist church, who had arrived with the father of Sim, who the family hadn’t been able to reach after the shooting. Authorities confirmed later Monday that Sim was among the dead.

The pastor was shocked by the shooting, as the school has a reputation as a religious school. “They just study Bible and nursing,” he said.

Monday’s body count was the Bay Area’s worst since the July 1, 1993, massacre at 101 California St. in San Francisco, when gunman Gian Luigi Ferri rampaged through two floors of a law office, killing eight victims before committing suicide.

Oakland Mayor Jean Quan appeared grim as she faced a news conference Monday evening. “No American mayor wants to have this situation,” she said. “We’ll have to question the availability of guns and the need for other services in our community.”

Oakland City Council President Larry Reid, in whose district the carnage occurred, said it’s “crazy when seven people lose their lives to an act of senseless violence. We have seven families whose loved ones won’t come home tonight. There are no words that anyone can offer them.”

A memorial service is planned for 6 p.m. Tuesday in the Berkeley Korean United Methodist Church, 303 Hudson St., in Oakland’s Rockridge neighborhood.

Staff writers Karl Fischer, Malaika Fraley, Matt Krupnick, Doug Oakley, Matt O’Brien, Jeremy Owens, Robert Salonga, Jason Sweeney, Thomas Peele and Angela Hill contributed to this story.