HOULTON – Investigators with the State Fire Marshal’s Office have determined that an apartment house fire last week that left four people homeless was the result of a human element.

Interviews concerning the fire are continuing, and evidence collected at the scene has been sent to the state Crime Laboratory in Augusta for analysis, Tim Lowell, a state fire investigator, said Monday.

The fire at 42 High St. was reported shortly before 2:45 a.m. last Friday, after a tenant called the Houlton Fire Department saying that she could see and smell smoke in the hallway of the three-story building.

According to a fire department official, the building was equipped with smoke detectors, but none of them had batteries.

The four people who lived in the three-story building escaped without injury.

The building reportedly was insured, but none of the renters had insurance on their personal belongings.

More than 20 firefighters from Houlton and Hodgdon fought the stubborn fire for nearly five hours. Three firefighters suffered minor injuries, but they were treated at the scene and were able to return to fighting the fire.

While fighting the fire, observations were made that led firefighters to suspect that the fire might not have been accidental.

Anyone who might have information about the fire should contact Lowell through the Maine State Police in Houlton at 532-5400.