BALTIMORE (AP) -- A security guard arrested on arson charges for a series of fires that damaged or destroyed homes under construction at an upscale housing development said he was innocent and insisted that authorities have the wrong person.
Aaron L. Speed, 21, is an employee of Security Services of America, a company hired to guard the development 35 miles south of the nation's capital.
``They have the wrong man,'' he told WUSA-TV Thursday shortly before his arrest. ``Everything that I'm doing, I'm doing willingly to prove to them that I am innocent. I'm taking a polygraph today that'll show them that I'm innocent.''
It could not be learned if a polygraph test was administered to Speed.
No motive was immediately known and a spokeswoman for the U.S. attorney's office said she did not know how many arson charges Speed faced. He was expected to appear Friday morning before a magistrate in federal court.
No one was hurt in the Dec. 6 fires, but a total of 26 houses were damaged, 10 of them severely, in what authorities described as the largest residential arson case in Maryland history. The fires caused $10 million in damage.
Because of the size of the 10-acre crime scene, authorities believe at least two people are responsible for the arsons. No information was available Thursday on additional suspects.
Investigators also said there was evidence that the arsonists tried to set 10 more blazes at the subdivision.
Early speculation was that the fires were set by environmentalists who believed the houses were a threat to a nearby bog. But no evidence has been found to support that theory, police said.
Linda Auwers, general counsel for the parent company of Security Services of America, said authorities asked the company not to comment. ``We are fully cooperating with the authorities in their investigation of this matter,'' she said.
Authorities searched the home of Speed's parents on Wednesday night and towed a car away, said David Jaillet, whose stepdaughter is married to the security guard. No one answered the door Thursday night at the house. A homemade ``No Trespassing'' sign was taped to the storm door of the ranch-style home.
Speed had suffered through several difficult family situations, including the death of a baby son this year and his own placement about 18 months ago in a foster home by an organization specializing in mental health treatment.
Jaillet said his stepdaughter and Speed married about a year ago and had twin boys earlier this year, but one of the boys died of intestinal complications.
Speed is a ``decent person,'' Jaillet said. Asked if he thought Speed was involved in the fires, Jaillet said: ``No, I don't think he is; it's not in his character.''
Jaillet said Speed had worked as a security guard for about a year and was a supervisor at the Hunters Brooke site.
The Washington Post reported last week that Speed had told the newspaper that he saw a blue van at the Hunters Brooke development the morning of the fires. He said he was visiting the guard on duty at the time. Speed told the paper that he could only see a driver and wasn't sure whether anyone else was in the van.
``It basically looked like they were trying to watch,'' he told the newspaper, referring to the van. ``I saw it lingering around. ... It kept passing by the construction site entrance.''
Firefighters had reported seeing the van leave the scene, the sheriff's office has said.