09/10/2012 06:46 pm ET Updated Dec 06, 2017

Brett Olson's Body Found: Missing Student Confirmed Dead (VIDEO)

The week-long search for 20-year-old Lafayette resident Brett Olson came to a tragic close on Sunday afternoon, when authorities discovered his body in the Sacramento River near the Butte-Glenn county line.

Olson, a student at California Polytechnic State University in San Luis Obispo, disappeared during a tubing event down the river on September 2, an annual float that takes place every year before the beginning of the school year. He was last seen around 1 p.m. that day at the "Beer Can Beach" just south of Chico State University.

His family spearheaded an aggressive search effort that took place throughout the past week, spawning #FindBrettOlson campaigns on Twitter and Facebook. A burrito restaurant in Lafayette raised $4,000 during a fundraiser in order to contribute to the efforts.

Chico police said in a statement that Olson drowned and thanked the community for their efforts to locate the young man. "It's significant that they spent essentially a week helping to look for him," Chico Police Lt. Mike O'Brien told ABC News. "And unfortunately it came to a tragic ending. But, their efforts were not in vain. They did the right thing."

A candlelight vigil will be held at Acalanes High School in Lafayette at 7 p.m. on Tuesday. Olson's family posted the following message on Facebook:

You all are our friends now. 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 res of our lives. the last time our son Brett was seen was about 4pm one week ago today. We are thinking that at about 4pm today, please pause and give a hug to someone close or send one to our son. May that bring each of you, and Brett, a feeling of hope, love, peace, and strength.

Click here to donate to the Olson family during their time of need. For more, watch ABC News' video report below: