A Lafayette family holds out hope that their loved one will be found after disappearing while tubing down the Sacramento River over the holiday weekend.
Brett Olson is a student at Cal Poly-San Luis Obispo but was visiting friends at Chico State.
He was last seen about 1 p.m. Sunday when he arrived at Beer Can Beach near Chico for a float down the river with thousands of other students who did it each year to mark the beginning of the school year.
Olson's parents and friends have handed out hundreds of fliers (pictured) this week in hopes of finding him.
A Facebook page "Let's Bring Brett home", had more than 70,000 members. Brett's father, Michael Olson posted on the page Thursday, "We remain positive and optimistic that we will find Brett. If anyone saw Brett after 4 p.m. on Sunday, please let us know."
Friends are fanning out on the streets, and on social media, hoping to get the word out and help police.
Twitter has also been abuzz with people tweeting and retweeting the hashtag #FindBrettOlson. Even stars have tweeted, including Miley Cirus, Howard Mandel, and Bay Area Olympians Maggie Steffens and Kerri Walsh.
"I think everybody realizes he's someone's brother and someone's son and someone's best friend," Kaaren Brickman said. "You know it just hits home for a lot of people."
Butte County sheriff's Sgt. Steve Collins told Bay City News 55 rescuers and volunteers were involved in the search as of Thursday morning.
On Wednesday night, crews searched two areas where Olson was most likely to be found, Collins said. An aerial search was also conducted using heat-sensing technology and California State Parks is conducting a land search as well.