Fire spread through a mobile home early Friday, killing four young siblings and their grandparents just hours after the family returned from a trip to Louisiana.

A family spokesman identified the victims as 6-year-old twins Jennifer and Jessica Church, their brothers Jarod, 7, and James Jr., 12, and their grandparents Franklin Church, 61, and Brenda Church, 57.

The children lived with their grandparents, two doors from their father's home, said family spokesman Tom Marcum, a minister at Mandarin Church of Christ. The children's mother lived in Louisiana.

Neighbors said the family had returned home around 1 a.m., two hours before firefighters arrived to find the home engulfed in flames. A burned van was parked in the driveway with a trailer attached to it.

The fire started in the dining room, but its exact cause had not been determined, said Tom Francis, a spokesman for the Jacksonville Fire-Rescue Department.

Neighbor Crystal Galbraith, 20, said she woke up after hearing an explosion. She looked out the window and said the whole house was on fire.

"There was no saving them," she said. "Those babies didn't have a chance for a life."