Thiede was last seen driving for either Uber or Lyft on Wilshire Boulevard just north of the 110 Freeway in Los Angeles.
Earlier on Monday, police found Thiede's auto and towed it away.
His mother, Janet Thiede, tweeted out Saturday that according to her family usage cellphone plan, her son or someone using his phone called 911 on February 12 and then hung up.
The image she portrayed was in stark contrast to the person that Joshua Thiede 's friends said they found in hospital, telling CBS that he appeared to be out of it.More news: Amazon gives Prime members perk at Whole Foods
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His 2014 sedan was being towed from where it was discovered south on Western Avenue around 4 p.m. on Monday, aerial video showed.
Ross Stracke, who lives on Kingsley Drive, said he noticed the Altima had a ticket on its windshield, which is likely what tipped off authorities to its location.
"They opened up, the bloodhound went in, the bloodhound went out, and then the bloodhound looked around a little bit", he described of the investigation.
"We're really getting concerned now", friend Kevin Young told KCBS-TV. "I got frightened when I saw the 911 [call] and called police", she said. In this photo, Prague's taxi drivers are seen in front of their cabs during a protest against unfair competition of the rival transport platform Uber in Prague, Feb. 8, 2018.
Janet said it's unlike her son to disappear and not contact anyone. Los Angeles Police Department spokesman officer Greg Kraft said he could not confirm Thiede's condition and when he arrived. His vehicle had been located in Koreatown earlier in the day. They've plastered posters all around the neighborhood, and are even speaking to people to see if anyone has seen the 6′ tall, 170-lb, blonde hair, blue-eyed man.