Authorities arrested a 28-year-old man Thursday on suspicion of sexually assaulting a 19-year-old female student on the Orange Coast College campus a day earlier, officials said.

On Wednesday around 4:54 p.m., police received a call regarding a man chasing and grabbing a woman on the campus located at 2701 Fairview Road, the Costa Mesa Police Department said in a news release.

Officers learned that the woman was walking near the horticulture department and the technology building when a man approached her from behind and forcibly groped her, police said.

A good Samaritan who witnessed the attack intervened as the woman cried out for help. The witness confronted the suspect, and the woman was able to run away.

The suspect had already fled the scene when police arrived. Officers initially were not able to find the victim either but campus safety officers found her a short time later at the school’s housing facility.

The college sent out a notification to students, faculty and staff that night to alert them of the alleged sexual assault and provided the description of the suspect, the department said.

The following morning around 4:30 a.m., campus safety officers were patrolling the grounds when they found a “suspicious male” near the campus’ Allied Health building. The man matched the description of the suspect and so they followed him to the area of Harbor Boulevard and Merrimac Way, while providing location updates to the police department.

Officers arrived and detained Alex Enrique Siliezar, 28, of Costa Mesa as a suspect in the alleged attack. He was arrested and later booked at Orange County Jail.

Detectives are seeking additional witnesses to the incident. Anyone who may have information is asked to contact Detective Jake Jacobi at 714-754-5178 or jjacobi@costamesaca.gov, or Sgt. Scott Stafford at 714-754-4933 or sstafford@costamesaca.gov.