LYNN – A lead investigator for the Lynn Fire Department says two major structure fires that occurred within the past month that left a total of 26 people homeless were likely caused by unattended space heaters.The most recent fire occurred Monday night at 185 Williams St., where a space heater was found on the second floor, Lt. Dave Legere said Wednesday.”The space heater was at the point of origin of the fire,” Legere said.He said the second-floor resident relied solely on the space heater to keep his bedroom warm.”We think something combustible was near it and probably set on fire.”Legere says the four-alarm fire Jan. 14 that destroyed two buildings and damaged a third at the corner of Chestnut and Lewis streets was likely started by a space heater as well. However, Legere cautioned that the official cause is still under investigation.The fire, which occurred around noon when temperatures never got above 20 degrees, likely started inside Roma hair salon in the Lewis Street building.”Most likely somebody left some kind of appliance on,” Legere said.Legere is waiting to speak with the last person who was believed to be inside the salon before the fire broke out. The woman purportedly left the business around 9:30 a.m. then hopped a plane that afternoon for a Carribean island and hasn’t returned to Lynn since.He said the fire broke through a wall and into an alleyway between the two buildings, which “acted like a chimney.” One of the appliances investigators eye as the cause of the fire is a space heater, he said.Unfortunately, Legere says, space heaters are the all too common cause of structure fires.”The higher oil prices go, the worse it gets,” he said.Among space heater usage tips recommended by firefighters, Legere says you should buy newer models that automatically shut off if the device tips over.And, “You have to keep combustibles at least three to four feet away from it,” he said. “It’s not safe unless you’re watching it all the time.”