Police are offering a reward of up to $5,000 for information that leads to the conviction of the person or people who set fires that destroyed two vehicles over the last two weeks.

Lt. Michael Lane and Jennifer Mieth, a spokeswoman for state Fire Marshal Stephen Coan, said the reward is offered through a state program, created in the late 1980s and funded by property insurance company underwriters in Massachusetts.

"They have offered up to a $5,000 reward for information leading to the arrest, prosecution and conviction of the offender or offenders," Lane said yesterday.

Detectives are investigating a string of fires that were started under one car Oct. 31. Two other vehicles were destroyed by fire, one on Nov. 11 and the other Saturday.

Early Saturday morning, a Jeep Wrangler belonging to firefighter Glen Asaro, 50, was burned on Prospect Street, according to police. The Jeep was parked outside the family's business. Early Nov. 11, Ellen Tasker, 34, lost her 1997 Honda Civic when it was set on fire in Prospect Square.

Another car, a red 1992 Buick Regal belonging to Rebecca Main of Prospect Street, was towed Nov. 11 for safekeeping after someone tried to light fires under the vehicle three times between Oct. 31 and Nov. 11. None of the fires caused major damage to the Buick.

No one has been injured in any of the fires.

Asaro said his Jeep was locked, and the rear window was broken out. The interior was destroyed by the fire.

A neighbor called police at 3:31 a.m. Nov. 11 to report Tasker's Civic was in flames. Police arrived and immediately called the Fire Department. Firefighters used about 800 gallons of water to extinguish the fire, but the car was a total loss.

Fire officials believe the blaze started in the Civic's rear seat, which Tasker said was unlocked.

The first car fire was discovered early Oct. 31 when police found and extinguished burning papers at 1:40 a.m. under Main's Buick, parked at the corner of Prospect and Elm streets.

An hour later, a cab driver reported another fire under the Buick. Firefighters extinguished a small stack of burning newspapers, according to Fire Department records. Minor damage was reported to the Buick.

Police reported in the Oct. 31 log that the patrolman who discovered the first fire, Kevin Hicks, saw a man in the area with short brown hair and a goatee wearing a white long-sleeve shirt and jeans. The cab driver reported taking someone matching that description to Rockport.

At 12:44 a.m. Nov. 11, a Shepherd Street woman reported another small fire under Main's Buick, parked in front of Eaton Pharmacy on Prospect Street. Police said the fire was out when Patrolman Joseph Catarino arrived.

This time the Buick was towed so it wouldn't be targeted again.

Detectives have patrolled the area on weekend nights in search of the arsonist.