FREMONT (CBS SF) — A 28-year-old bicyclist was killed early Wednesday when he was struck by a car on a Fremont street, authorities said.

Fremont police said the fatal collision took place around 5:10 a.m. on Boyce Road between Stewart Avenue and Auto Mall Parkway. The force of the crash left debris spread across the roadway.

Arriving officers found the victim in the street. Efforts to aid him were unsuccessful and the man was declared dead at the scene.

The crumpled windshield and dented hood on the vehicle give some indication about the force of the impact and how fast the driver was going.

“He was rear ended. And at this point, the information shows he rolled up onto the car, and rode on the car for probably several tens of feet and then was thrown off of it as the vehicle braked,” said Fremont Police Sgt. Daniel O’Connell.

Fremont police spokeswoman Geneva Bosques said the 25-year-old driver from Ceres initially left the scene, but came back and was cooperating with investigators.

“This guy says he drove to where he works in the area and then he came back. And some other co-workers came back with him. And they took the bike off the car, because it was stuck on the car,” said O’Connell.

The driver was cooperative and gave a statement to police, and likely drove some distance in the dark with the mangled bicycle embedded in the windshield.

Larry Eldridge told KPIX 5 he was just arriving at work and saw the driver in the parking lot.

“He was actually outside of his car, when I saw him. He just had his arms folded and I couldn’t tell anything was wrong,” said Eldridge.

That was before 5 a.m. And since Fremont police say the driver didn’t call until 5:11, that meant the driver waited for at least 10 to 15 minutes before calling 911.

When asked what he thought the driver was doing, Eldridge replied, “I don’t know, maybe grieving? I have no idea. He was just, sitting there.”

O’Connell was similarly stumped when asked his thoughts on the driver’s state of mind.

“I don’t know. He’s the only one that can answer that question,” said O’Connell.

There was no immediate word on what caused the collision. The 28-year-old biker was wearing dark colored clothing

Boyce Road was shut down while investigators searched the scene. Anyone who witnessed the crash was asked to contact the Fremont police department.

It is unknown if the cyclist would have survived had he gotten medical treatment right away.

The driver was heading into work from his home near Modesto, about an hour and a half away, which meant he likely left his home around 3 a.m.

Investigators say fatigue might have been a factor.

Officers were investigating whether drugs and/or alcohol played a factor in the collision. Fremont police said the driver has been cooperative and gave a blood sample. He has not been arrested or cited with any violations just yet.

This was Fremont’s fifth fatal traffic collision in 2019.