A Bowie County Sheriff spokesman says the body of one child has been taken to the Southwest Institute in Dallas for an autopsy.
Texas Rangers believe injuries to the child are consistent with a homicide.
The autopsy is expected to be back within the next 2 weeks.
Law enforcement and fire investigators continue to sift through the rubble for more clues.
Officials have released the names of the mother and children killed in Wednesday's house fire.
The mother's name is Amanda Doss. The children are 11-year-old Gweneviere Doss and 8-year-old Texas Johnson.
Investigators now suspect arson.
A house fire 7 miles southwest of Texarkana on the 1200 block of FM 991 left 3 people dead Wednesday morning.
Fire officials say all 3 people were inside the house when they arrived around 5 a.m. Firefighters were able to pull an 11-year-old girl out of the house and performed CPR on her, but she died on the scene. The mother and an 8-year-old boy were also inside, however, firefighters were unable to reach them due to the intense flames.
It took 10 fire departments and 2 hours to get the fire under control.
The Texas Rangers, ATF, Texarkana police and Bowie County Sheriff's Office are also at the scene.
One Texas Ranger tells KMSS, they are treating the fire as a crime scene.
KMSS has a crew on site and will bring you more details as they become available.