KSWO television in Lawton, Oklahoma, reports officials are trying to figure out who possibly murdered an inmate inside his jail cell after the man called 911 several times.

The Lawton GEO prison inmate was found lying on the floor of his cell late last week. Christopher Glass was found dead, officials have not said what killed him. A toxicology report is being prepared.

Officials say Glass called 911 several times, but his voice was never heard on the recording. Here comes the creepy part: his killer's voice may have been captured.  According to KWSO, the other person in the recording was heard to say:

"Whether or not you're a dead man. Just hang up."

Police so far have not been able to identify the other person, and they have not conclusively said if that person was responsible for Glass' death. But this is the first time we've ever heard of a potential murder victim calling 911 from inside a jail cell!