Transcript for Frantic search underway for missing Uber and Lyft driver

We move on now for the desperate search for a missing Uber and Lyft driver. His mother says her son or someone else was using her son's phone, calling 911 24 hours after he disappeared. Here's ABC's kayna Whitworth tonight. Reporter: Tonight, a frantic search underway for a missing Uber and Lyft driver. Friends taking to the streets and putting up fliers around Los Angeles in hopes of finding 29-year-old Joshua Thiede. This is extremely out of the ordinary for Josh. I mean, he would at least tell one person he's taking off. Reporter: Thiede was driving a 2014 black Nissan Altima vanishing last Sunday. Friends and family say a 911 call was made from his phone the next day. We are not sure why he made that phone call. There is no transcript of the phone call, because there was not a conversation recorded. Reporter: His mother finding the call in his phone log and alerting police. That same phone pinging at an address near his home on Thursday, and since that time, Nop contact. And still no sign of Thiede or his car. Tonight, the Los Angeles police department telling his mother they are investigating several tips that have recently come in. David, both Uber and Lyft say they are working with law enforcement and will continue to assist however they can.

This transcript has been automatically generated and may not be 100% accurate.