Around 7:30 a.m. Wednesday, the Tucker Fire Department responded to a reported fire in the Bloomo community of Neshoba County. It took about thirty minutes to extinguish the fire.
Officials say they believe the three occupants tried to get out before being overcome by the smoke.
Authorities say Leigh Ann Fortenberry, 47, and her three-year-old grandson, Ethan Tyler Moore, were pronounced dead at the scene in the Bloomo community off state Highway 486.
Fortenberry's 11-year-old daughter, Kayleigh, was pronounced dead at Neshoba County General Hospital.
"When they first went in the front door, they found one just inside, as soon as they went in that door," said Myron Williams, fire chief of Tucker Volunteer Fire Department. "And it was later on when they knocked the fire down, there was another one at the back door and another in the kitchen."
Neighbors say that Fortenberry will be missed.
"It's going to be empty. It's going to be empty up here now," said Jimmy Anderson, a neighbor. "Just seeing her up here, you'll miss them. Especially summer time. She's out cutting grass or whatever."
The official cause of the fire has not yet been determined, but authorities say that propane heaters may be to blame.
"The fire was pretty extensive in the living room area around some infared heaters," said Williams. "There was a lot of stuff in the house itself, in the trailer, a lot of clutter."
Williams said that a cluttered table was very close to the heaters. He believes that something on the table probably caught on fire, starting the fatal blaze.
The Associated Press contributed to this report.