The suspect's name has not yet been released.
California Highway Patrol officials said the semi was heading northbound on Etiwanda Avenue at approximately 2:15 a.m. when it ran a red light at San Bernardino Avenue near the border of Fontana and Rancho Cucamonga.
Authorities said the semi struck an SUV and a small Ford sedan. The two aboard the SUV suffered minor injuries, but the driver of the Ford died on impact.
"I thought my heart stopped. It was crazy. I thought I (saw) my cousin just die right in front of me," said a witness, who did not want to be identified. His cousin was in the SUV; he survived the crash.
The driver of the semi did not stop after the crash, so the witness chased him down about a half a mile to the corner of Etiwanda Avenue and Napa Street.
"I was in front of him. I was telling him to pull over; he wouldn't pull over," the witness recalled. "I was kind of braking, but it kind of looked like he was going to try to run me off the road."
The driver then approached his car, so he asked him, "Did you see what just happened? You hit my cousin." But the driver denied that he hit anyone.
The witness called 911, as the suspect ditched his 18-wheeler and fled on foot.
For four hours, officers and K-9 units scoured a large area of Fontana that included a truck yard and train tracks, but the search came up empty. CHP said their bloodhounds lost the trucker's scent at Calabash and Whittram avenues, but he was eventually arrested.
"I believe that without the witnesses and without what this witness did for us and the information he gave us, it would have been that much more difficult to apprehend someone," said CHP Officer Johni Russell.
Authorities said the semi-truck involved in the crash was never reported stolen, and investigators were able to track down the owner of the big rig to a trucking company in Fontana. It was unclear if the suspect in custody is the owner of the big rig. The suspect was positively identified by the witness.
It was also unclear if drugs or alcohol played a factor in the crash.
According to the CHP, the trucker will be charged with a fatal hit-and-run accident and will also be cited for running a red light.