Murder charges were filed Monday in the burning death of Texas child-welfare caseworker Terry Leigh Lee, allegedly at the hands of her new boyfriend — who has shown "little remorse," police told FOXNews.com.

John Marshall Dodd, 42, is behind bars, accused of pouring gasoline on his girlfriend of just a few months after striking her during an ugly fight, then setting her on fire. Dodd initially lied to neighbors and investigators about what happened, saying Lee had been burned in a kitchen accident, according to authorities.

He faces life in prison if convicted and is currently in the Montgomery County Jail on $250,000 bail.

More than 90 percent of Lee's body and face were scorched in the attack late Saturday night at her home in Conroe, Texas, a suburban community about 30 miles outside of Houston. The 44-year-old caseworker of the state's Child Protective Services died Sunday night of her injuries at an area hospital.

Conroe Police Sgt. Mike Tindall told FOXNews.com in a phone interview that authorities pieced together what happened based on a statement Dodd gave them, as well as evidence they gathered from the scene — but said the suspect hasn't expressed regret at what he allegedly did to Lee.

"He has been what I would describe as somewhat cooperative," Tindall said. "He really has shown very little remorse throughout."

Tindall said the couple had been out on a brief date earlier Saturday evening for about an hour-and-a-half or two hours before returning back to Lee's house, where Dodd would occasionally spend the night. They got into a quarrel, which escalated and became violent, he said.

"At this point, we don't know what the argument was about," said Tindall. "The argument turned physical. The victim suffered facial fractures ... He struck her with something, whether it was with his hands or some type of weapon he picked up in the house. At some point, he went out into the garage of the residence, retrieved a can full of gas, poured the gasoline on her and ignited it."

Police found several lighters in the house, though they aren't certain what Dodd used to set his girlfriend on fire. Lee never regained consciousness, so she wasn't able to shed light on what happened.

"We were never able to speak with her before she passed away," said Tindall.

He said there hadn't been any history of violence between the victim and the suspect as far as police knew.

"We have not had any calls of any violence between him and her," he said. He declined to comment on whether Dodd had any known history of domestic violence.

There was no evidence that alcohol played a role in the fight or the attack, according to Tindall. An autopsy report was pending.

Neighbors told police they called 911 after Dodd ran to their home with the story that there had been an explosion, according to The Associated Press. Tindall said the suspect had changed his story a number of times before admitting that he doused Lee with gas and set her on fire.

Lee was a Montgomery County caseworker and the 2005 winner of the Texas CPS caseworker of the year award. She has a teenage daughter from a previous marriage who is currently staying with her father in the Houston area, according to Tindall.

He said he knew the victim from her work as a child advocate for the county.

"I've known her for several years," Tindall said. "She was a very nice lady. She was always very helpful to us and our investigations. ... She loved working for the kids. She was a strong advocate for children."

A spokeswoman from Child Protective Services said those in the department were "all saddened and shocked by her loss."

"Terry did so much for families and children. She had so much to give," CPS's Gwen Carter told FOXNews.com. "She always went above and beyond, and never complained. She really wanted to help people."

Carter said her coworkers had no indication that there was any violence in Lee's relationship, and she didn't personally know that Lee was dating Dodd.

Though Tindall wouldn't comment on Dodd's criminal history, public records show that the suspect has had several run-ins with the law, according to The Houston Chronicle.

Dodd is no stranger to prison, having spent time there for attempted sexual assault during a burglary, the newspaper reported.

He was sentenced to five years in jail in 1993, though he was freed on parole in 1995, the Chronicle reported. No further details on that case were immediately available, but public records also indicate that Dodd has been arrested numerous times over the years on theft, criminal trespass, criminal mischief and other charges.

Lee was visited throughout the day Sunday by family, friends, coworkers and associates who came to her bedside at Memorial Hermann Hospital-The Medical Center.

"They were all visibly upset," Tindall said. "They were trying to figure out what happened."

The woman's sister, Margo Duke, told the Chronicle that Lee had been "a champion for children. ... She was auntie to so many children. ... She helped everyone."

The paper reported that Duke, 45, said she'd never met Dodd but knew that her sister had been seeing him for about three months and that he worked at a fitness center.

Tindall said investigators have not been able to determine for sure what Dodd does for a living.

He told police that he is a personal trainer, but he isn't on record as having worked for any gyms or fitness facilities in town, according to Tindall.