Cal Poly’s president and student body president are asking students to use social media to help spread the word about missing theater arts major Brett Olson, who disappeared near Chico last weekend.

“We ask you to distribute the flier (attached) via social media and also encourage you to join the Facebook group "Let’s Bring Brett Home," college President Jeffrey D. Armstrong and ASI President Katie Morrow said in a joint letter to the “Cal Poly community.”

“This will assist Brett’s family and friends with bringing more awareness to this serious situation.”

“Please keep Brett’s family and friends in your thoughts during this challenging time,” they continued. “We hope our next report to you regarding Brett will be positive in nature.”

Armstrong and Morrow asked anyone with information to call the Glenn County Sheriff’s Office at 530-934-6431 or the Chico Police Department at 530-895-4994.

Law enforcement personnel near Chico continued their search for Olson, who went missing from a weekend festival on the Sacramento River, and have expanded their search to the city of Chico.

Olson, 20, disappeared during the annual Labor Day “river float.” He was last seen about 1 p.m. Sunday on a gravel bar known as Beer Can Beach, near the town of Hamilton City, about eight to 10 miles from Chico.

Students often stop at the beach as they float down a short section of the Sacramento River, according to Undersheriff Rich Warren of the Glenn County Sheriff’s Department.

More than 10,000 people participated in the float Sunday.

Warren said Thursday that there was no new information, but officials were exploring all possibilities — checking out the river and its banks and using aircraft, watercraft and dogs.

It is possible that Olson went into the city of Chico, he said.

Olson’s loved ones have set up the Facebook page. As of Thursday afternoon, it had nearly 60,000 subscribers.

Olson, from Lafayette, was visiting friends at Chico State. He is described as 6 feet 2 inches tall and 160 pounds with short brown hair. He was last seen wearing dark shorts, with no shirt or shoes.