Maryland fire investigators are hoping a black Honda Accord will put them on the trail of whomever burned a construction trailer last weekend, the sixth suspicious fire since mid-March at a construction site.

The Accord was seen about 2 a.m. Sunday being driven from the scene of a fire that destroyed a contruction trailer parked near the intersection of Snowden River Parkway and Tamar Drive in Columbia. The unattended trailer and its contents were valued at $25,000.

"We'd like to know a lot more about that car," said Jack Waldner, a deputy state fire marshal. "It is one of the best leads we have so far."

Waldner said the Columbia fire probably is related to another construction trailer fire that occurred about an hour earlier off Iron Bridge Road near Guilford Road in Savage. That fire caused about $10,000 damage.

The two fires could be connected to a pair of fires that destroyed construction trailers in March, Waldner said.

The two March fires, which totaled $24,000 in damage, occurred in the same general area as Sunday's fires and were set about the same time at night.

"I know the two fires in March are probably related. And we know the two fires the other night could be. But it is too early to say whether they all are related," Waldner said.

He added that the fires appear to have been set in a similar fashion, but he would not disclose details.

Howard County Fire Chief Donald Howell said arson is suspected in a fifth construction trailer fire, which occurred April 30 at a site off Meadowridge Road near Mayfield Avenue, causing a $2,000 loss.

And on June 6, a homemade pipe bomb destroyed a portable toilet at a construction site off Knights-bridge Road and Horsham Drive in Savage.

The Meadowridge Road fire differed from the other four in that the trailer was parked in an isolated location and protected by a security fence.

The pipe bomb incident occurred near one of the March trailer fires but is the only fire involving an explosive.

Fire investigators ask that anyone with information about the Accord or the fires call the state's arson hot line at 1-800-492-7529. Callers could be eligible for up to a $5,000 reward.