By CNN Staff
The blaze that killed two Boston firefighters last week was unintentional and caused by a welding operation, Boston fire officials said Friday.
But prosecutors have yet to determine whether anyone was criminally culpable, Boston Police Commissioner William Evans told reporters.
The nine-alarm fire occurred on March 26 at a brick brownstone in Boston's Back Bay neighborhood.
Lt. Edward Walsh, 43, and firefighter Michael Kennedy, 33, were killed. Thirteen other firefighters were injured.
Walsh had worked with the Boston Fire Department for close to 10 years, and Kennedy had 6½ years on the job. Walsh was married with three children, all under the age of 10. Kennedy was a veteran of the U.S. Marine Corps.
Walsh and Kennedy were trapped soon after entering the building. They were later found in the basement, where the fire appeared to have started.
Fueled by strong winds, flames quickly engulfed the four-story building. An explosion at one point threw a number of firefighters down stairs.
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