Arson investigators combed the scene of a massive blaze in Paterson Saturday that destroyed five apartment houses.

Firefighters worked for nearly six hours to extinguish the flames of the Mill Street fire, which began just after 4 p.m. Friday. A neighbor says some of the homes destroyed were crack houses involved in a multi-home drug ring. The neighbor, who asked not to be identified, says there were tunnels between the homes used to move drugs.

Investigators say the old construction of the homes, as well as how close together they were, could have contributed to how quickly they burned. A fire destroyed a row of similar homes just 100 feet away from the blaze back in October.