Four Oklahoma men set off on a bike ride Sunday night.
Mystery surrounds four Oklahoma men who went out for a bike ride Sunday and haven't been seen or heard from since, authorities said.
The four close friends left together at 8 p.m. Sunday and were reported missing on Monday by their families after calls to their cellphones went directly to voice mail, police said.
The police chief in Okmulgee, a small city about 40 miles from Tulsa, said he has never encountered a case before where four people disappeared at one time.
"I can't make sense of the actual set of circumstances because it is so unusual," chief Joe Prentice told local reporters.
“At this point, the evidence tells me I have four missing adults. I have no evidence there’s any violence involved at this point, we always consider that a possibility in any missing persons case and we’re not discounting that possibility," Prentice said, but investigators have not identified any person of interest, he added.
The missing men were identified as Mark Chastain, 32; Billy Chastain, 30; Mike Sparks, 32; and Alex Stevens, 29.
“Someone out there knows something. I don’t care if it’s good or bad please just come forward. These men have families,” Mark Chastain’s wife, Jessica, told a local station.
Police said they believe the men visited a gas station and two salvage yards. One of the men's cellphone lost battery power or was turned off at one of the junkyards, Prentice said.
Investigators received reports of the men being sited, but none of those reports could be confirmed, the chief said.
On Friday, officers began culling surveillance videos and tracking GPS data.
Anyone with information is asked to contact the Okmulgee Police Department at 918-756-3511.