Brent Eller, principal of Loftis Middle School, right, listens during a news conference Friday in front of the sheriff's office in Chattanooga as Hamilton County Sheriff Jim Hammond announces the arrest of two juveniles involved in the September 2012 arson at Loftis. The two suspects, who are unaffiliated with the school, will be charged with aggravated burglary, arson, reckless endangerment, and vandalism over $60,000.

Detectives may make more arrests in an arson case at Loftis Middle School that resulted in more than $150,000 in damage.

The Hamilton County Sheriff's Office arrested two 17-year-olds in the September 2012 fire, Sheriff Jim Hammond said at a news conference Friday.

Hammond said at least one of the teens has turned 18 since the crime and he may attempt to have both tried as adults.

As many as 50 people were interviewed, and Detective David Sowder said numerous search warrants were executed before the arrests.

"This was a crime of opportunity, and we're very fortunate to make the arrests we have," Sowder said.

Sowder said the investigation is ongoing and he could not give details about what led authorities to arrest the teens, who had no ties to the school.

Lee McDade, assistant superintendent at Hamilton County Schools, described the arrest as "a big relief" for the school system.

On Sept. 17, the Dallas Bay Volunteer Fire Department was called to the middle school on Camp Columbus Road in Hixson.

Firefighters extinguished a fire in one room. Sheriff's officers and Red Bank police SWAT teams cleared the building, but no one was found, according to authorities.

Investigators found broken windows, ruined classrooms and blinds ripped off windows. The main office was ransacked and, when the sprinkler system was triggered, a dozen classrooms sustained water damage.

Multiple fires had been set throughout the building, and cash and electronic equipment were taken.

Initially, authorities said they had reason to believe one of the suspects had been seriously cut during the break-in.

"That's a key part of our ongoing investigation," said Sowder.

He wouldn't say whether either of the teens had suffered such an injury or whether any of the electronics were recovered.

A $10,000 reward was offered in November for information leading to the arrests of those responsible.

Darryl Hill, special agent with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, said it's unclear whether anyone will receive the reward. He said authorities are waiting until all arrests are made and the case is prosecuted.

Hammond said the arson and vandalism investigation was "a very serious case."

"We put a lot of resources into it," he said.

Contact staff writer Beth Burger at bburger@times freepress.com or 423-757-6406.