KNOXVILLE, Tenn. (WATE) — As investigators work to determine what caused a fatal fire along Mississippi Avenue, the Knoxville Fire Department has released audio recordings between dispatchers, callers, and firefighters.

911 calls show just how frantic the usually-quiet Mississippi Avenue was early Monday morning.

Caller 1: There’s a fire. The address is Mississippi Avenue, 226.

Caller 2: My neighbor’s house across the street from me is on fire.

Audio recording between neighbors and 911 dispatcher

Another caller could see the blaze from her phone and house camera while at work.

I’m literally watching it on my camera. Looks like the porch is on fire. People at my house next door is throwing water on it.

Audio recording between neighbor and 911 dispatcher

One caller told a dispatcher she believed a little boy and his grandfather lived inside the house. Once first responders arrived, they learned both victims were trapped inside.

Firefighter: We’ve got a victim here inside of the building.

Moments later, Battalion Chief Robby Copas called for another medic unit.

Battalion Chief Robby Copas: Dispatch from command, start me another medic unit this way. 10-4. Go ahead and start me a chaplain.

Dispatch: We’re on the phone with them now, sir.

“They found them real close to each other,” said Copas. “They were both in the back side of the house may be trying to get out the back door. They found the child, basically, he was in the kitchen, and the adult was in the laundry room slash going out the back door.”

Firefighters, including Rosie Forsythe, worked to get them out as fast as possible.

“Trying to give them every chance we can,” explained Forsythe. “We moved them from the back of the house, pulled them forward to the front room where we were met by other crews who took them outside.”

Radio chatter: Fire’s out. They’re overhauling. We’re three and 76 in the front yard.”

Radio communication

“That means they’re working a cardiac arrest,” Copas told WATE.

As crews worked to put out hotspots, both victims were transported to the hospital where they later died.

“I met the mother on scene and my heart goes out to her,” said Forsythe.

Audio between first responders

Although the investigation into Monday’s fire is ongoing, investigators discovered a piece of evidence that could explain why both victims were unable to escape.

“During that fire, we did find a smoke alarm,” said KFD spokesperson Mark Wilbanks. “That particular smoke alarm had taken a lot of heat so it was melted. We were able to determine that it did have a battery in it.

“However, what we don’t know is, was the battery charged? Was it a good battery? We don’t know if the smoke alarm actually activated. Typically, these will go off for a long time, even after we’ve put the fire out, we will hear them chirping and going off so most likely, we feel like, it probably did not go off.”

KDF now urges everyone to not only make sure they own a smoke alarm, but also make sure it works. For information on how to ensure your smoke alarm works properly, click here.