Human Interest 4 Close Friends Still Missing Since Leaving for a Weekend Bike Ride in Oklahoma Police — who believe two of the men had cell phones with them that now go straight to voicemail — say there are no signs of foul play "at this point" in the investigation By Jason Hahn Jason Hahn Jason Hahn is a former Human Interest and Sports Reporter for PEOPLE. He started at PEOPLE's Los Angeles Bureau as a writer and reporter in 2017 and interviewed the likes of Kobe Bryant, Arnold Schwarzenegger and Tom Brady. He has a B.A. in English from the University of California, Berkeley, and a Master's degree in Journalism from Columbia University. He previously worked for Complex Magazine in New York City. People Editorial Guidelines Published on October 13, 2022 04:30PM EDT Photo: Okmulgee Police Department (4) Authorities are searching for a group of four men who have not been seen since going out for a bike ride over the weekend in Oklahoma. On Wednesday, the Okmulgee Police Department announced that four friends — Mark Chastain, 32; Billy Chastain, 30; Mike Sparks, 32, and Alex Stevens, 29 — have been missing since Sunday. "All four are close friends and are believed to have left Billy Chastain's home on the west side of Okmulgee on Sunday at around 8 PM," the department said in a statement on social media. "All were reportedly on bicycles. Two of the men are believed to have cell phones with them, but attempts to call go straight to voicemail." Mark, Billy, and Mike were reported missing by Mark's wife on Monday night, while Alex's mother reported him a few hours later. The department said there are no signs of foul play "at this point" in the investigation, but they are receiving help from the District 25 Violent Crime Task Force. Missing Hiker Found Dead Days After Texting Her Husband That She 'Got Off Course' Thanks to interviews with potential witnesses, investigators placed Steve at a smoke shop in south Okmulgee late Sunday afternoon. Another witness reported seeing Billy and Mark near a local YMCA on Monday morning. Okmulgee police said they are working to confirm the sightings. PEOPLE reached out to Okmulgee Police Department on Thursday afternoon for more information. Mark's cell phone was traced to an area in South Okmulgee, but it was since turned off or lost power. "Officers have checked that area and found no sign of any of the men," Okmulgee police said in the statement. Body of Missing Maine Teenager, 14, Found After 5-Day Search In an update on Wednesday, police chief Joe Prentice said he instructed search teams to rest for the night. "Task Force investigators have met," he said. "These men are exhausted. I am sending them home to get rested and we will start fresh tomorrow, unless something time sensitive comes in over night. I do not plan to give any additional updates until tomorrow." RELATED VIDEO: Missing Colo. Teen Found Alive Days After She Disappeared Following High School Football Game On Thursday morning, Prentice said there was no new information to "base a search on," and that the department would focus its efforts on reviewing surveillance footage "from the path we believe they traveled and following up reports of sightings today." Mark's wife, Jessica Chastain, told NBC affiliate KJRH that the friends usually stay close to home. "They don't go far — never," she told the station. "If they're alive, someone's holding them hostage or something," she later added. "But I don't see four grown men being held hostage by one person."