WESTWOOD, Mass. (AP) — Investigators have determined a house fire that killed a Massachusetts man last week was an accident caused by a wood stove.

Forty-seven-year-old Michael Lennon was killed Jan. 10 in the blaze in Westwood.

Authorities say it remains unclear whether the stove failed, an ember escaped or if combustible materials were placed too close to the stove.

State Fire Marshal Peter J. Ostroskey urged people to be careful when heating their homes with wood.