Police negotiators talking to the Orlando nightclub gunman at first weren't sure if the person they had on the phone was actually in the Pulse nightclub.
Audio recording of shooter Omar Mateen's conversations with police negotiators were released Monday after a judge ruled they should be made public.
The city of Orlando previously had released a transcript.
The audio recordings didn't stray from the transcript but captured police negotiators strategizing among themselves about how best to talk to Mateen, who hung up several times.
A police official can be heard saying he's not convinced the person on the call is in the club.
The lead negotiator says it sounds like Mateen is calling from "a very sterile environment" like a home or apartment.
But another police official says he could be in an office or bathroom.