The sheriff's office has not released his name because they are still getting information from one of the alleged victims to establish his identity, Sgt. Raymond Kelly said.
A 17-year-old girl said a stranger approached her between two cars as she walked to school on San Miguel Avenue near Lux Avenue around 7:50 a.m. Tuesday, Sgt. J.D. Nelson said.
The man grabbed her crotch but the girl spun away and ran to the high school, Nelson said. She notified campus security personnel who contacted a deputy sheriff assigned as a school resource officer, Nelson said.
Campus security saw a Japanese model truck that matched a description of the suspect's vehicle and stopped it when it pulled into a driveway, Nelson said.
Sheriff's deputies found the truck's license plates inside the truck cab, Nelson said. A bread knife fell out of the suspect's jacket when he got out of the truck, Nelson said.
Sgt. Raymond Kelly said the man also is suspected of attempting to kidnap another Castro Valley High School girl shortly before the incident involving the other student.
"Both girls were touched and both got away," Kelly said. "It appears he was driving around and was targeting young girls," Kelly said.
The suspect will also be arrested for attempted kidnapping Kelly said.
Kelly said deputies also found a seat cover the size of a blanket in the back of the truck.
The sheriff's department is contacting other law enforcement agencies regarding any similar near abduction cases involving the suspect, Kelley said.
Anyone with information is asked to call Deputy Rick Gonzales at (510) 667-4906