Police at California State University Bakersfield didn't have the authority to arrest the person suspected of attacking three students in the past three days, Police Chief Marty Williamson told 23ABC News.

"We didn't have the legal authority to make the arrest," Williamson said.

Williamson said his department -- University Police -- has received criticism over the incident, but he cited a statute that says officers can't arrest someone who commits a misdemeanor outside of their presence.

In this case, the suspect was banned from campus for seven days.

"If he comes back in those seven days, then he's committing a misdemeanor in our presence," Williamson said. "Then he can be arrested."

RELATED: CSUB's police department is investigating three reports of assaults on campus

Williamson added that while the victims were all students, the suspect was not -- and he told officers he was waiting on campus for a friend at the times of the attacks.