Firefighters who reported to where Chamber's vehicle was found burning had said that she told them "Eric" was responsible.
Several firefighters testified Tuesday and Wednesday in the trial of Quinton Tellis in Batesville, Mississippi, about 50 miles (80 kilometers) south of Memphis, Tennessee.
In December 2014, Chambers was discovered beside her burning vehicle on a rural Panola County road with severe burns to 98 percent to her body.
It's alleged that Mr Tellis then drove ms Chambers' vehicle with her inside it to the back road, ran to his sister's house nearby, jumped in his sisters' auto, stopped to pick up gasoline from a shed at his house and torched Ms Chambers' auto and her.
If convicted of the Chambers murder, Tellis would spend the rest of his life in prison. She claimed they Chambers and Tellis hugged, but she believed Chambers was afraid to do so.
Cole and additionally a few specialists on call told members of the jury Wednesday that Chambers reacted "Eric" when asked who had set her ablaze.
Prosecutor John Champion told jurors that they will see graphic photos of a burned Chambers and they will hear from about 35 witnesses. She said all three of them hung out that morning to smoke marijuana for one to two hours before they dropped Tellis off near a grocery story on Highway 51.
The prosecution reportedly argued that Tellis - previously described as a "habitual" criminal offender - tried to suffocate Jessica after the two had sex in her auto that night. He said he asked Chambers' her name, then asked, "What happened?" and she responded saying, "Eric set me on fire". Chambers was burned alive on a back road in Panola County in December 2014.
He said he saw Jessica standing in the road with the auto burning near her and immediately got a blanket and went to Chambers' aid. "She didn't say any other name, she didn't mention any other person. She said 'Jessica, '" Cole read, "She stated multiple times, 'Eric set me on fire'".
Palmer also stressed the apparent discrepancy of Jessica's description of her killer. Quinton Tellis' DNA was reportedly found on those keys, the prosuction says.
"He insisted this is not something he would do", Palmer said.
Daniel Cole, the Director of Emergency Operations in the county, wrote a report saying he arrived on the roadside where Chambers' auto was ablaze to find her covered in blankets on the ground with first responders.
Mr Tellis faces another murder indictment in Louisiana, where he's accused in the torture death of Meing-Chen Hsiao, a 34-year-old Taiwanese graduate student at the University of Louisiana at Monroe.
First up, Champion. Describing Chambers as a "beautiful, blonde-haired 19-year-old", he set the basis of the state's case.