(AP) -- Students wrapped up classwork and prepared for finals Thursday as the UCLA campus tried to regain a sense of normalcy a day after being rocked by a murder-suicide that prompted a lockdown and an enormous police response.

The engineering department, site of Wednesday's shooting, remained closed during the investigation but the rest of the school buzzed with typical end-of-semester activity. Students crammed for next week's tests while on sunny lawns and in libraries at the University of California, Los Angeles. Seniors tried on their caps and gowns.

Sophomore Gus Lee said he was shaken by the killing of Dr. William Klug by a former student, calling the events of the day before "pretty frightening and tragic." He planned to attend an evening vigil for the slain 39-year-old biomechanical engineering professor.

Investigators said Mainak Sarkar, a 38-year-old former engineering graduate student, shot Klug and then turned the gun on himself. The gunfire led to a lockdown on the sprawling UCLA campus with around 60,000 students and staff members. Helicopters swarmed as armed SWAT officers searched buildings while students huddled under desks.

Police said Thursday that they suspected Sarkar also killed a woman whose body was found in Minnesota and may have been planning to kill another professor. Authorities have not publicly identified the woman or the unharmed professor, also of UCLA's engineering faculty.

Dr. Brennan Spiegel said he'd never met Klug but felt an obligation to address the tragedy at the start of his public health class.

"I've been thinking about him all night. I told that to my class," Spiegel said. "I said I didn't know him, but I would imagine that if he knew we were here talking about this event, that he would want us to continue our mission of education, teaching and learning. That's what we do here at UCLA."

Klug's colleagues and friends described him as a kind, devoted family man and teacher who didn't appear to have conflicts with anyone.

Chancellor Gene Block called him a "respected, dedicated and caring faculty member."

Klug received a master's degree from UCLA 1999 and a doctorate from Caltech four years later. He began teaching at UCLA's Department of Mechanical and Aerospace Engineering in 2003. He is survived by a wife and two young children.

"Let us remember and be grateful for the wonderful gifts and talents Professor Klug shared with us at UCLA," Block wrote in a letter to students and faculty.