By Maria Medina

ALAMEDA COUNTY (KPIX 5) — A sunny stretch of Interstate Highway 580 may have led a bus carrying Tesla employees to fatally rear-end the car of an Alameda County sheriff’s deputy on Friday.

Alameda County sheriff’s deputy Sroeuy Khin died one day before his 51st birthday, leaving behind four kids and his wife.

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“It was just so sudden, you know. Devastating,” said the deputy’s brother Ronnie Khin.

“Why was the bus still going if his car was almost at a complete stop? That just didn’t make sense. I mean did the bus not see him?” Ronnie Khin asked.

Tesla employee Bun Soth was riding on the commuter bus when the collision happened.

Soth said, “That impact, that moment it hit everybody felt it, everybody just instantly woke up and were just like: What happened? What happened? Did we get in an accident?”

He describes the driver of the bus driver contracted by his company as always alert and safe.

“He takes his job very seriously, “Soth said.

Investigators say the driver claimed he didn’t see Khin’s car until it was too late because the sun was in his eyes

Soth says he believes him.

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“I actually thought about sitting in the front seat,” Soth said.

But he didn’t that morning because, he says, of the sun on that part of the Altamont Pass where the crash happened.

Instead, he took a middle seat on the bus to get some rest. A decision, he says, he regrets.

Soth said, “I could’ve probably sat on the front seat and I could’ve possibly helped prevent that situation.”

Deputy Khin lived in Stockton where Bun also lives. He said he never met him, but knew he was a pillar in the Cambodian community.

Ronnie Khin said, “Thanks for being my brother, honored, blessed for him to be a part of my life.”

Deputy Khin’s funeral is planned for this weekend.

Flags remain at half-staff in his memory at the jail where he worked. This is the second deputy death for the department in the last few months.

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Police in Santa Cruz join the nation in flying the American flag at half-staff. It’s honoring fallen officers for ‘National Peace Officers Memorial Day.’The 143 officers who died last year will be added to the National Memorial in Washington D.C.