GPS records show the father of two parked his big rig on Interstate 5 near the Merced County town of Santa Nella just after midnight early Wednesday.
Around that same time, a passerby claims to have seen him walking to the back of the trailer with his hazard lights on just before he disappeared.
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Satwant's heartbroken son Rajan Bains spoke to Action News on Thursday. He said the disappearance was out of character for the 53-year old.
"He wasn't depressed, he's happy. I just had a baby boy; he loves him so much."
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Around 5 am Wednesday officers arrived to discover the truck's engine still running and doors unlocked.
Bains' cellphone and wallet were also found in the cab of the Freightliner.
"He doesn't go anywhere without his phone," said Rajan Bains. "He doesn't use his card he only uses cash. All the cash was still in his wallet. No one stole anything. We just want to find him."
Search and rescue teams are checking both sides of Interstate 5 including the nearby Delta-Mendota Canal.
Anyone with any information on the disappearance is asked to call the police.