$20K reward offered for student who vanished at Michigan State University

It's been nearly three months since 18-year-old Brendan Santo vanished while visiting friends in East Lansing, Michigan, the weekend of the Michigan-Michigan State football game.

There have been no clues yet as to what happened to the Grand Valley University student who disappeared on Halloween weekend, but the search for him continues, and his family is not giving up hope. "We just want Brendan back," they told ABC News.

"It is unfathomable to believe in this day and age someone can just disappear," Brendan's aunt, Dawn Brewer, said. "Our family is desperately begging anyone with information to come forward even anonymously."

Santo was last seen around midnight on Oct. 29 on MSU's campus, near Yakeley Hall, authorities said. He was wearing grey sweatpants, a black T-shirt, a Detroit Red Wings cap and Converse high tops, police said. He's about 5-foot-10 and 160 pounds.

Santo's friends believed he was heading toward the Brody neighborhood, where he was staying with other friends, but he never arrived. His phone was at 0% battery when he went missing, the last message he sent was around 11:45 p.m.

The surveillance cameras in Yakeley Hall were not working the night Brendan went missing, MSUPD confirmed, and there were no other cameras in the area.

"Finding out what happened after Brendan left Yakeley Hall is the key to finding Brendan, or at the least adding another piece to this horrible puzzle," Brewer said.

Santo's friends reported him missing the next morning. Brendan's vehicle remained in the last location it was parked, and there is no indication he left the East Lansing area, according to MSUPD.

Soon after Santo's disappearance, the FBI joined state and local agencies in the search, which included efforts by foot, drone, helicopter and boat. Authorities utilized multiple K9 teams early in the investigation, including cadaver dogs.

According to MSUPD, multiple cadaver dog indications on the Red Cedar River near Santo's last known location along with his digital footprint led investigators to focus on the Red Cedar River, though they are exploring other possibilities.

"As a parent, family member or friend, you want to turn over every boulder as fast as you can to get the information you need to find your loved one. We understand an investigation like this can take time, but it has been very difficult," Santo's aunt said.

There have been no sightings of Santo to date, and none of his belongings have been found, but interest in his disappearance has only grown. Volunteer searches, charity events and various fundraisers have helped raise awareness, as has social media.

There have been two extensive civilian searches with over 800 volunteers scouring the area looking for Santo's black red wings hat, blue iPhone, car key or gold necklace. Several MSU students and local citizens have continued to search every day, according to the family.

"Many of these people do not know Brendan or our family, but have taken the time and energy to help us every day … our family continues to be overwhelmed by their support and dedication," Brewer told ABC News.

The family-run Facebook page called "Bring Brendan Santo Home" has reached over 43,000 members, donned BBH Warriors. Many are participating in a #bringbrendanhome flyer challenge, which encourages people to print Brendan's flyer and post a photo with the hashtag "#bringbrendanhome." Flyers have been posted across the country and beyond, according to the family. An Instagram account created to getting the word out continues to grow, as more join the search for the missing teen.

"Our family continues to have hope and pray he will be returned safely," Brewer said. The family is following the mantra "Keep the faith" until they bring Brendan home.

The reward for any credible information about Brendan's whereabouts has grown to over $20,000. The tip line can be reached at 844-99-MSUPD (844-996-7873), tips@police.msu.edu or Crime Stoppers of Mid-Michigan 517-483-STOP (7867) https://www.crimestoppersofmidmichigan.com/.