HAMILTON CITY — After a weeklong search that drew thousands of online followers, the body of Lafayette student Brett Olson, an Acalanes High School graduate, was found Sunday morning in the Sacramento River, authorities said.

Olson, 20, a student at Cal Poly San Luis Obispo, had been missing since he disappeared Sept. 2 during a Labor Day weekend river-tubing event that draws thousands of young people. He was with several friends in an area known as “Beer Can Beach” when his friends lost track of him about 4 p.m.; he was reported missing the next day.

“Brett … has been such a bright light in all of our lives,” said Juliana del Beccaro, 20, who had been friends with Brett since first grade. “The fact that he’s not going to be with us anymore doesn’t mean that he’s gone to any of us.

“We know that whether he is physically here or not, his light is going to be shining. He personally affected everyone he came into contact with.”

Del Beccaro recalled “the guy who I used to run around on the playground with in the third grade,” saying he had grown into an “outgoing, creative amazing person.”

Olson’s parents, Michael and Elizabeth, identified his body after a fisherman spotted it a mile or two downriver from where he disappeared and alerted a search and rescue team. The couple had been joined by dozens of their son’s friends and other well-wishers in searching for him all week in the Chico area.

After identifying the body, Olson’s parents hugged and wept as they stood near the river. They could not be reached for comment later in the day.

A statement attributed to Michael and Elizabeth Olson on a Facebook page dedicated to finding Brett told well-wishers that “there are not words to describe how moved we have been by everything all of you have done for us. You filled us with hope and love this week which we will carry with us for the rest of our lives.”

The search for Brett Olson had been largely aided by social media sites, with almost 100,000 people joining the Facebook group and others using Twitter to draw attention to the search. After his body was found, condolences and remembrances poured in on both sites.

That strength of response was both a reflection of Olson’s character and a source of strength for his family, del Beccaro said.

“So many people just lit a fire up under this story and made sure that Brett’s name was not going unheard,” she said. “It really meant a lot to (his family) that so many people were backing them up.”

Sunday morning, Olson’s parents had met with more than 100 volunteers who planned to spread out across Chico to look for Olson and respond to reported sightings.

Since the stretch of the river north and south of where Olson was found had been searched again and again for a week, it was thought that he might be found in Chico or elsewhere.

Before the volunteers left for the day, Olson’s parents thanked them for their efforts. A local woman said a prayer. It was apparently about the time that the search was starting that Olson’s body was found in the river.

When searchers learned that Olson’s body had been found, some of his friends returned to the parking lot where they had met earlier in the morning. About 25 young people could be seen in small groups, talking to each other.

“I’m in a state of shock,” one young woman said.

A vigil is planned to remember Olson at 7 p.m. Tuesday at Acalanes High in Lafayette. Funeral plans have not been announced.

The Chico Enterprise-Record contributed to this report.