Ten people were killed, half of them high school students, when a truck slammed into a tour bus full of college hopefuls heading for a campus tour in northern California on Thursday, Reuters quoted police as saying.Five students, three chaperones and the drivers of the bus and FedEx truck were killed, according to the California Highway Patrol and Humboldt State University, which was to host the students' visit."All of a sudden I heard people screaming," Jonathan Gutierrez, 17, told NBC's "Today" show. He had been asleep before the impact, he said.Gutierrez, who suffered facial cuts, said the aisle of the bus filled with smoke and students broke windows to escape. "It was a very surreal moment," he said.The Los Angeles Unified School District, the largest in Southern California, said 19 students from 16 of its high schools were on the bus tour headed to Humboldt State, but could not say whether any of the students who died were students at district schools.Among the dead was a Humboldt State recruiter, 26-year-old Arthur Arzola, who worked for the university out of the Southern California community of Rancho Cucamonga, the Sacramento County Coroner said on Friday morning.The school's website names Arzola as a counselor and recruiter. In a biography on the site, Arzola characterized himself as hard-working, compassionate and friendly, and described the university as offering "incredible opportunities that change the world for the better.