OAKLAND, California  - The gunman who killed seven people in a rampage at a California religious college lined up his victims and shot them one by one, Oakland police chief told CNN Tuesday.

"This was a calculated, cold-blooded execution in the classroom," CNN quoted police chief Howard Jordan as saying.

Jordan said the shooter, allegedly an ethnic Korean identified as One Goh, was believed to have walked into the building housing the college, took a receptionist hostage and then went looking for a particular female administrator.

When he realized the administrator was not in the building, he shot the secretary and then lined students up against a wall and shot them one by one, Jordan told CNN. "I'm going to kill you all," the gunman allegedly told the students.

After the shooting, the gunman left the classroom, reloaded his automatic weapon and then fired into several classrooms before leaving the building and driving off in a victim's car.

"This happened within minutes," Jordan said. "We don't think the victims had any opportunity to resist, any opportunity to surrender."

In an interview with ABC television, Jordan said the victims were six women and a man ranging in age from 21 to 40, and were from Nigeria, Nepal and Korea. All were students at the Christian school, Oikos University.

"We've learned this was a very chaotic, calculated and determined gentleman that came there with the specific intent to kill people," Jordan said.

He said the gunman surrendered to police after driving to neighboring Alameda, California, where he called his parents.