The victims have been identified as 27-year-old Lindsay Groce and her 13-month-old daughter, Hailey Gardner.
Police are waiting for the medical examiner to determine the causes of death. They say no identification was found on the bodies, and there were no obvious injuries that looked like they would have caused their deaths.
Police also say the bodies are connected to the wrecked car that was nearby.
A passerby called 911 about 8:20 a.m. Tuesday to report seeing the wrecked car in a field near Altamesa Boulevard and Bryant Irvin Road in southwest Fort Worth.
However, the bodies were not found until about three hours later by a man who was fixing a broken fence.
Detectives are currently working to pinpoint the timeframe of the crash, according to police.
"There's always deer in that field, and I was looking for deer and I saw the car," said Amber Bentley, who was driving by Tuesday morning when she spotted the wrecked car and called it in.
A gold Toyota Camry had crashed into a tree, and the impact was so great that both front airbags had deployed.
Once officers arrived on scene, they searched the car and field but came up empty.
About two hours later, a man who'd come to fix a fence to keep grazing cattle in discovered the bodies, which were about 500 feet from where the wrecked car came to a rest.
Lindsay's body was reportedly covering Hailey's body.
"Our homicide unit, as well as our traffic investigation unit, are both trying to determine exactly what happened out here," said Natosha Tucker with the Fort Worth Police Department.
From her Facebook page, FOX 4 has learned that Lindsay was an artist who loved to paint.
She got married in 2012 and liked to blog – she had two of them.
The last entry from one blog is from April 2013. In it, Lindsay describes the struggles of living in California, saying, "If you are reading, please pray for me and my family. My husband and I are going back to no home, no job, and pregnant. This is going to be very difficult. Our ‘plan' is hopefully to get some government aide to buffer us until one or both can stabilize a job. "