A 53-year-old woman and her three grandchildren -- ages 10 months, 2 and 4 -- are dead following a fire late Tuesday afternoon at an Oceanway mobile home. A fourth child was treated for injuries and now out of the hospital.

The victims were identified as Sheila Swearingen, 53; Janet Fowler, 10 months; Rachel Fowler, 2; and Richard "Bubba" Fowler Jr., 4.

The fire tore through a double-wide mobile home about 5:40 p.m. Tuesday. Jacksonville Fire Rescue officials said Swearingen and one child died at the scene on Palmetto Street. Family members said two other children died a short time later at a hospital.Family of fire victims

(Pictured: Richard and Jennifer Fowler with their
three oldest children, Hattie, Richard Jr. and Rachel)

Six-year-old Hattie Fowler was rescued by a boy who saw the fire when he was riding his bike. She was in good condition at Wolfson Children's Hospital and was released Wednesday.

"My heart? Pain. It won't go away," said Jennifer Fowler, the children's mother and the daughter of Swearingen. "I don't how I'm going to deal with it. No, I don't think I can. But I know I'm going to be there for Hattie. The family's keeping together on this."

The Jacksonville Sheriff's Office and the Fire Marshal's Office are investigating but do not suspect foul play.

IMAGES: Fire destroys home, takes 4 lives
Funeral expenses donation account at EverBank: 0010021914
Routing No. 063092110

Ashley Carr, a spokeswoman for the Fire Marshal's Office, said investigators learned Wednesday the origin of the fire was in the bedroom adjacent to the living room. She said that is not the room the grandma and infant Janet were in. They were in the master bedroom.

Carr doesn't believe anyone was in the room that caught fire, but she couldn't say for certain.

Mobile home site of fatal fire "My mom come out the room," Jennifer Fowler said. "She said she smelled smoke and then she opened the playroom where the two younger kids were at. She seen the fire and says she was just trying to get them out, and then the Fire Marshal said it was one big boom."

Investigators said K-9 dogs did not alert them to any accelerants. They are still working with the Jacksonville Sheriff's Office homicide unit to determine the cause of the fire.

Investigators also do not believe the fire was caused by an electrical malfunction. They are hoping to get a better idea of the cause after talking to Hattie and by autopsy results.

It's unclear if there was a smoke detector in the home.

“This is a tragic case in all manner, but the community really stepped up and tried to do the best they could do," JFRD Chief Martin Senterfitt said. "There's tragedy and there's heroics involved.”

UNCUT: Fire Chief Martin Senterfitt

JFRD investigators said the children's parents, Richard and Jennifer Fowler, were incarcerated at the time.

Richard Folwer and Jennifer Fowler mug shots Richard Fowler (pictured on left), 54, was arrested Saturday on charges of child neglect, possession of a controlled substance and resisting an officer without violence. His bond was set at $17,500. He was released at 1 a.m. Wednesday.

Jennifer Fowler (pictured on right), 31, has been in jail since March 13, when she was arrested for violating her probation. Her previous charges include making a false report to law enforcement in December 2013, domestic battery in September 2013, and disorderly intoxication, public disturbance and criminal mischief in August 2012. She is now on home detention.

The parents were told of the fire tragedy by jail staff Tuesday night and were later released from jail on various conditions.