University police received a 911 call about a man bleeding from the head. (Representational)

A retired administrator was fatally stabbed Monday on the first day of the school year at California State University at Fullerton, with the assailant seen fleeing the scene, police said.

The victim, who had returned to work in international student affairs, appeared to have been targeted, police said. But they said they do not know why he might have been singled out.

"We do not believe there is an active stabber on the loose," Lt. Jon Radus of the Fullerton Police Department said.

Law-enforcement officers found a backpack underneath the victim's car, Radus said, and a bomb squad from the sheriff's office in Orange County found an incendiary device and "numerous items that could be used to conduct a kidnapping."

Radus declined to describe the latter items in more detail but said the incendiary device was a bottle of flammable liquid with matches taped to it. He said authorities believe the backpack was left unintentionally by the suspect and was a further indication of a targeted attack.

University police received a 911 call shortly before 8:30 a.m. about a man bleeding from the head, said Radus, whose agency is assisting campus police. When officers responded minutes later to a parking lot near an administrative building on campus, they found a man in his late 50s sitting in a silver Infiniti sedan and bearing stab wounds across his body.

Despite efforts by city and campus police to save his life, the man was pronounced dead by Fullerton Fire Department workers when they arrived, Radus said.

The witness who called 911 saw the assailant running away and described him as a man in his 20s.

Bloodhounds from the Orange County Sheriff's Office were deployed to try to find him, Radus said at a news conference. He said they were not aware of threats made against any faculty members.

"Our hearts and prayers go out to the family of the victim and all those affected by this tragic and senseless loss," Framroze Virjee, president of Cal State Fullerton, said in a written statement to campus. "The safety and support of our Titan family remains our top priority, now and in the hours and days to come."

Ellen Treanor, a spokeswoman for the university, said Monday afternoon that university officials and police were not publicly identifying the victim, pending notification of next of kin.

School officials said on social media that the retired administrator had returned to campus to work as a consultant.

Student leaders did not immediately respond to requests for comment.

The public university has about 40,000 students and more than 4,000 faculty and staff members.