``At this point, we have not found any evidence foul play was involved, but we can't rule anything out,'' said sheriff's Capt. John Allard.
Autopsies were scheduled for the children who only were identified as 5-year-old twins, and their siblings ages 3 and 2.
Emergency crews reached the Gilbert-area home about 1 p.m. on Saturday and found the singlewide home engulfed in flames.
``It's a mobile home and they can burn pretty rapidly,'' Allard said. ``There was nothing they could do to save the children who were in the home.''
The children's mother, Natasha Pierce, 23, escaped with cuts and severe burns was taken for treatment in Augusta, Ga., he said.
The severe damage to the structure has hampered efforts to pinpoint what started the blaze. Allard said it was standard practice to seek a second opinion from SLED in fatal fire cases.
The children's father, C.J. Sanders, raced home to find the charred remains of his home.
Sanders, an employee of Scott's Furniture Co. in Lexington, said the twins had just started kindergarten at Gilbert Elementary School.
Pastor Dennis Jackson, of Tabernacle Baptist Church in Batesburg-Leesville, described the family as caring.
``They had those kids in church every Sunday,'' Jackson said.
Jackson summarized Sanders' feelings Saturday afternoon. ``His main statement is, 'That was all I had.' ``