COURTLAND, Miss

. - Jessica Chambers was a regular at the rural convenience-store gas station where Ali Fadhel worked, and the two often chatted. On Saturday, she came by in a dark-colored sweater and pajama pants that looked like sweats. She put $14 worth of gas in her car, more than the $5 or so she usually purchased, he said.

"I asked her, 'Why are you putting so much gas?' She said, 'I'm going somewhere,' " Fadhel said.

An hour and a half later, she was found along a back road, her body on fire, severe burns covering her. She was able to briefly talk to firefighters before she was airlifted to a Memphis hospital, where she died of thermal injuries.

Chambers, 19, had told the cashier she was going to make a stop before going home, he told the Associated Press.

"If she knew she had a problem with somebody, she would have told me," Fadhel said.

On her way out, Chambers got a call on her cellphone, he said. After she pumped gas, she re-entered the store, bought cigarettes, and drove away, headed south on the highway, he said.

Yesterday, officials said they were still working to determine who doused her with a flammable liquid and set her on fire. They said they'd made no arrests and didn't expect any in the near future, but that they were considering all possibilities and following up on all tips.

"In all the years I've been doing this, this is an absolutely horrendous, horrendous case," District Attorney John Champion said at a news conference. He described Courtland as a small community rocked by the death and said he hopes people will come forward with information.

"There's just not a lot of street talk out there about who may or may not have done this," he said, but "we feel like somebody out there has heard something."

Jay Hale, an assistant district attorney who handles cases in Panola County, confirmed that Chambers spoke to firefighters - perhaps giving them clues - but said he couldn't discuss what she said.

"She was able to communicate. It was difficult," Hale said.

"We know what she said, but we are not commenting on what she said," Champion confirmed at the news conference.

Champion told the AP that officials have a preliminary autopsy report and are awaiting the final one but won't release either because they are part of the ongoing investigation.

Among the clues police are examining: surveillance video showing Chambers at the gas station, cellphone records from numerous people and interviews with potential witnesses, Hale said.

The surveillance video shows Chambers walking toward the front door of the convenience store in Courtland, which is about an hour south of Memphis, Tennessee. She then stopped, turned to her left, and walked out of the picture.

Hale said he could not comment on Fadhel's statements about Chambers' time there.

Not much was immediately revealed about the young woman's background by authorities, but Chambers' grandmother said, "She was just a sweet little girl."