A Katy man now considered a "person of interest" in one of two blazes that broke out at George Bush Park was posing as a member of the Houston Fire Department at the fire, officials said on Friday.

Lonnie Ray Henderson, 28, was charged with felony impersonating a public servant after firefighters and Harris County deputy constables spotted him riding an all-terrain vehicle in the fire zone.

"He was driving around by himself and saying that he called in the fire," said HFD Fire Marshal Richard Galvan.

Henderson also was wearing HFD bunker gear - a firefighter's heavy overcoat, boots and helmet.

"It was the full ensemble," Galvan said.

The gear came from HFD, although Henderson has no record of ever having been with the department.

HFD officials said they were investigating how Henderson got the equipment but said there have been reports of bunker gear thefts.

"And we don't loan out our bunker gear," Galvan said.

Henderson had been a volunteer with the West I-10 Fire Department. He has not been with the volunteer organization for more than a year, said an official who couldn't comment further citing the investigation.

The suspicious blaze erupted about 11:45 p.m. Thursday in the northern section of the park along the 15800 block of Interstate 10. The fire charred about 27 acres before fighters were able to bring it under control.

HFD officials said Henderson's actions also aroused suspicions. Their firefighters do not ride all-terrain vehicles by themselves at a fire scene.

"You're in a crew of four and there's always a back-up," Galvan said.

Officials got nowhere when they asked Henderson what he was doing at the fire.

"He refused to answer any questions that our investigators had for him and he requested to go home," Galvan said.

Harris County prosecutors charged him Friday with impersonating a public servant.

The fire came hours after firefighters gained control of another blaze in the park that scorched about 1,500 acres. That fire broke out about 3 p.m. Tuesday in the 16700 block of Westheimer Parkway and raged for a few days.

HFD arson investigators said they have not ruled Henderson out as having any responsibility in the earlier fire.

The cause of both fires still remain under investigation, Galvan said.

Henderson has a criminal record in Harris County, including a 2008 arrest for theft. He admitted guilt in exchange for probation, which he completed in May.

In 2010, Henderson pleaded guilty to misdemeanor driving while intoxicated and was sentenced to a fine a 30 days in county jail.

Dale Lezon, Andrew Richardson and Lindsay Wise contributed to this report.

mike.glenn@chron.com