Chambers had burns on about 93 percent of her body when she was found along a rural back road on December 6, 2014, the prosecutor said. She died hours later at a Memphis hospital.
Tellis faces life in prison without parole if convicted, according to an April 18 court filing in which state prosecutors disclosed they wouldn't seek the death penalty.
Chambers said Tellis repeatedly lied to investigators about spending time with her in the hours before she was found. He also said that Tellis had repeatedly asked Chambers for sex, and she had denied him.
Champion said cellphone records show that Chambers and Tellis - who had met about two weeks before her death and had become friends - were together twice on the day she was burned.
The duo rode around in her car for a while that morning before Chambers dropped off Tellis at his house and she went home to take a nap, the prosecutor said.
Chambers then picked up Tellis about at 5.30pm (local time) and they went to a fast food restaurant, Champion said.
Citing statements Tellis made to investigators, the prosecutor said Tellis and Chambers had sex in her car later that evening.
Champion said he believes Tellis suffocated Chambers and thought he had killed her.
Tellis then drove Chambers's car with her inside it to the back road, drove the car to his sister's house nearby, jumped in his sister's car, stopped to pick up gasoline from a shed at his house and torched Chambers' car and her, Champion said.
"Horrific burns," Champion said. "Horrific pain."
Chambers was found walking on the road - wearing only underwear in 4.4C temperatures - when a passing motorist spotted her shortly after 8pm, Champion said.
Surveillance video showed Jessica Chambers was at a gas station less than two hours before she was found. Wearing a sweater and pajama pants that looked like sweatpants, she put $14 worth of gas in her car, more than the $5 or so she usually purchased, Ali Fadhel, a clerk at the gas station, told The Associated Press in the days after her death.
"I asked her, 'Why are you putting so much gas?' She said, 'I'm going somewhere,'" Fadhel said.
On her way out, Chambers got a call on her cellphone, Fadhel said.
Her car keys were later found nearby, and they had Tellis's DNA on them, Champion said.
Authorities have said previously that Chambers was on fire when she was found.
Champion said Tellis first told investigators he only saw Chambers on the morning of her death.
Tellis later acknowledged they were together in the evening, saying he met her to sell her marijuana and that he had sex with her in her car, Champion said. The prosecutor also said Tellis's alibi was fabricated.
Defense attorney Darla Palmer meanwhile claims her client is wrongly accused. She said Tellis was buying a pre-paid debit card miles away in Batesville at the time Chambers was burned.
Palmer also said eight first responders who treated Chambers asked her if she knew who did it.
"She said 'Eric set me on fire',: Palmer said. "She didn't say any other name."
In his opening statement, Champion acknowledged that the first responders did hear her say the name "Eric" or "Derek." Champion said she could have been saying "Tellis,", but the damage done to her throat made it sound different.
Palmer told jurors that Tellis never confessed to the killing.
"He insisted this is not something he would do," Palmer said.
About 20,000 telephone numbers were analysed in the investigation. Witnesses will include cellphone data experts, Champion said.
Tellis could face life in prison without parole if convicted of capital murder. He is also facing another murder indictment in Louisiana.
The 29-year-old is accused in the torture death of Meing-Chen Hsiao, a 34-year-old Taiwanese graduate student at the University of Louisiana at Monroe. No trial date has been set in that case.
- AP
