Nolan Wells' Enhanced Audio From Emergency Call Raises Questions

Nolan Wells' friends sound like they thought he was dead during their frantic call for help as their boat was sinking off Horn Island ... at least according to some people's interpretation of background audio from the emergency call.

TMZ enhanced the audio ... and it sounds like someone in the background might be saying, "Is he dead?" You can hear the moment 12 seconds into the audio above.

Some folks online also swear they hear someone saying "Nolan" ... right before you can clearly hear someone say, "Oh my God."

In other parts of the call it seems like someone might've said ... "Check his chest" and "wake up." You can clearly hear the caller yell, "shut the f*** up."

To be clear, none of those interpretations have been confirmed ... and the muffled conversation leaves plenty of room for people to hear different things. Listen and decide for yourself.

Still, the audio has prompted online sleuths to comb through every second for possible clues about what unfolded at Horn Island.

As TMZ previously reported ... the caller sounds panicked while telling the Sea Tow dispatcher the boat is sinking and its bilge pump isn't working.

The caller also struggles to answer basic questions before eventually providing the boat's GPS coordinates.

Nolan's friend Warren Hudson claims a member of their friend group was "panicking" while trying to convince Nolan to leave with them ... allegedly yelling, "Nolan, get the f*** on the boat."

Nolan's friends say he ultimately remained on Horn Island when their boat was towed away. His body was found washed up on the island two days later.

The day Nolan's body was found, the Jackson County Sheriff's Department released a statement stating "no foul play was suspected."