A 23-year-old Fairfield University student remained in critical condition Tuesday, while police and fire officials continue to investigate what caused his SUV to burst into flames last week in Tunxis Hill Park and set him on fire in front of a horrified Little League crowd.

Justin Hervey, of Armonk, N.Y., was taken to Bridgeport Hospital's burn unit after the Thursday night incident, where he remains for treatment of severe burns to much of his body.

According to Assistant Fire Chief Christopher Tracy, the fire marshal's office has determined the fire that engulfed Hervey began in the interior of the Chevrolet Tahoe he was driving.

"We do have it established that the body of the fire was in the passenger compartment," Tracy said Monday.

Lt. Michael Gagner, head of the Police Department's detective division, said evidence from the vehicle has been sent to the State Police crime lab for analysis to determine how the fire started and if there was a mechanical problem with the SUV with New York license plates.

Hervey, who was still conscious when emergency personnel arrived at the field, indicated he had pulled into the parking lot because of trouble with the vehicle. The fire erupted shortly after 6 p.m. Thursday, fire officials said.

Officials from both the Police and Fire departments said it could take several weeks before the investigation is complete.

Meanwhile, four Little League coaches are being praised for their quick action Thursday night in coming to the aid of Hervey, who fled the SUV engulfed flames.

Witnesses at the Little League game said they heard a popping, explosion-like sound and turned to see a man screaming as he ran toward them as flames covered his body. The Chevrolet Tahoe he was driving burned about 200 feet behind him.

The four coaches -- Jim Carolan, Vincent Giacomazza, John Pierce and Peter Porazzo -- saw the fire, sprinted from the field at the Melville Road park, leapt a fence to the parking lot, then grabbed a blanket to smother the flames burning Hervey.

Carolan said he and the other coaches instructed Hervey to "stop, drop and roll" to extinguish the flames.

"The thing I was most impressed with was the composure of the coaches," Carolan said. "They instructed the guy to roll. ... It's what they teach the kids in school."

Giacomazza was treated Thursday at a walk-in clinic for burns to his hands and arms.

Assistant Fire Chief Scott Bisson said the coaches' actions "were heroic and should be applauded, as they risked their personal safety to help another person in need."

Fire officials returned over the weekend to speak to the players about the incident, Tracy said.

Police Chief Gary MacNamara also praised the efforts of the coaches, saying they gave Hervey a chance to survive.

Mike Horyczun, Fairfield University's director of media relations, in a statement confirmed that Hervey was a part-time student at the college.

"The university community has been asked to keep Justin and his family in their thoughts and prayers," he said.

Horyczun said the university is monitoring Hervey's situation closely and extended support to his family and friends. "The office of Counseling and Psychological Services has offered support to students who may need assistance in dealing with this difficult situation," he said.

While police said Hervey was lucky the coaches were there to help them, MacNamara said it was "horrific" that the children playing at the field had to witness the "tragic" scene. Hervey's clothes were burned off his body and he suffered "significant" burns, MacNamara said.

"Unfortunately many of them had a clear view of this," Carolan, the team's manager, said Friday morning. "The kids were very shaken up. It's not something a kid or adult ever wants to see. It was awful they had to see it."

Carolan credited two parents for moving the children to centerfield, away from the flames.

Sgt. Suzanne Lussier, spokeswoman for the Fairfield police, said the players, 10 to 12 years old, were in the Little League fall program. They are students at Fairfield Woods Middle School and Jennings Elementary School, she said.

Fairfield Woods Principal Gary Rosato, in an email to parents, said each sixth-grade homeroom teacher addressed the incident with their classes as a whole in order to allow students an opportunity to talk about it.

The three guidance counselors and other support staff have been talking with individual students and parents "as the need arises."

Rosato addressed the entire sixth grade at lunch in order to acknowledge the event, alleviate some anxiety, and offer the help of the various adults in the building if students want to talk further. "All things considered, the students and teachers are handling it well," the principal said.

School officials are prepared to offer counseling to students upset by the incident.

Bisson said the fire was shooting out of the Tahoe windows when he arrived. Debris, including glass and pieces of the car's exterior, were scattered around.

Witnesses noticed the fire's unusual ferocity, saying "something was keeping the fire burning."

Carolan also said he noticed the explosion's sound was different than what he expected.

"It didn't sound like the movies," he said. "It was more of an air explosion, then the cabin was on fire and the windows exploded 30 feet. There was glass everywhere."

Carolan said he saw the car running as he pulled into the parking lot, about five minutes before the explosion.

"I thought he was getting ready to leave," he said.

Staff writers Genevieve Reilly, Tom Cleary, Pat Pickens and Frank Juliano contributed to this report.