This house on the corner of Commonwealth and Hollywood Ave has been vacant for years. But it's hardly secure. Three times people have broken into start fires. Once in January, once Sunday morning and one more today...

Fire Information Officer Dennis Leger says, "Now again Monday morning there is a separate fire here at 75, someone lit a fire under the front stairwell."

At least 75 Commonwealth is still standing. Another arson last weekend destroyed the vacant house next door. All that's left now is a pile of rubble. It's been a year of many arsons.

The fire department could not provide official figures, but our news archives show at least 10 arsons since January, sometimes in occupied buildings.

Leger says, "There is a lot of reasons why that happens I mean there is a lot of homeless people in the city and there is a lot of drug use going on and people are dropping things and it's accidental and it appears to be suspicious to us but it's actually not the case that they set it."

The suspects are often hard to find and the cases can be hard to prove.

Leger says, "There is this gray area between the two where we think that's what happened but we can't prove it so I mean the actual cases of proven arsons are really low."

The Arson Reward Program is being used to help solve the arson fires here on commonwealth and will pay up to $5,000 to anyone who has information leading to an arrest and conviction.