By Holly Yan, Deborah Bloom and Cheri Mossburg
LOS ANGELES (CNN) — Two people were killed in a murder-suicide at UCLA on Wednesday, prompting a campuswide lockdown and forcing hundreds of terrified students to hide in buildings.
The situation was contained by shortly after noon, and there was no ongoing threat to to the campus, Los Angeles Police Chief Charlie Beck said. He said police found a weapon, and no suspects remain at large.
UCLA said the campus reopened Wednesday afternoon. Classes were canceled for the rest of Wednesday, but are expected to resume Thursday.
Beck said the shooting took place in a small office in the engineering building. He said he did not know whether the dead were students.
Authorities had received reports of an active shooter in or near the building, Los Angeles Police Officer Tony Im said.
Officials put the campus on lockdown as authorities investigated. Throngs of police with long guns patrolled the streets of the campus of more than 40,000 students.
SWAT officers and dozens of squad cars filled the area as police tried to clear campus buildings floor by floor.
Freshman Teddi Mattox said she was in a cafeteria getting breakfast with about 100 other students when the shooting occurred.
“We got the alert and a woman said, ‘This is not a joke, everyone get to the back of the dining hall because we have to stay away from the windows,'” she said.
“We’re crowded back here, we’ve been here for at least an hour and a half. People are crying, they’re nervous, they’re shaking … I have not stopped shaking for the last hour and a half.”
Los Angeles police will lead the shooting investigation. Agents from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives also headed to the scene.
LAPD issued a citywide tactical alert, meaning shifts of officers on duty could be extended.
Police urged residents to avoid the UCLA campus.
CNN law enforcement analyst Tom Fuentes said locking down a large university in an urban area is a “monumental task.” UCLA’s engineering building is in the middle of a very densely populated part of Los Angeles.
UCLA’s final exams are scheduled for next week, with graduation set for Friday.
The engineering school’s senior class dinner was scheduled for Thursday night.
According to UCLA, the school is known as the “birthplace of the Internet” because in 1969, the first transmission on what would become the Internet was sent from the engineering school’s Boelter Hall.
CNN’s Amanda Wills and Stella Chan contributed to this report.