The cause of a three-alarm fire at a Copley Street home in May was concluded to be "undetermined" by the State Fire Marshal.

"The Middlesex District Attorney’s Office has determined that there is insufficient evidence that the fire at this address was intentionally set," said the district attorney spokeswoman, Stephanie Chelf Guyotte.

Fire investigators said in a June report the fire was started on the front porch close to the front doors, which remained intact and closed. He said an aged, dry holiday wreath on the porch caused sufficient fuel to ignite the siding of the house and surrounding surfaces. These combined combustible materials made it easy for the fire to reach a heat level to climb the porch ceiling and then spread along the house.

Homeowner Kim Covino, who was not present during the fire, said the "holiday wreath" was natural pine garland from Christmas twisted in lights she hadn't unwrapped yet. The coil was on the floor of the front porch to the left of the front door. 

"That's what ignited the fire, I think," Covino said.

Investigators said in their original report although there isn't information on what material ignited the fire, they do believe there was human action involved and asked law enforcement to step in.

The DA's office along with the Winchester Police and Massachusetts State Police conducted an extensive and thorough investigation, Guyotte said.

"Based on the investigation and review of all information available, this office has determined there is insufficient evidence to support a criminal prosecution," Guyotte said.

The investigation is now closed on the fire that caused $1 million worth of damage to the home and another $250,000 in household content.

“There was an aggressive interior fight which prevented damage to the new addition to the house," Winchester Fire Chief John Nash said. "The part that burned is about 100 years old."

Firefighters from the Arlington, Stoneham, Winchester and Woburn departments responded to the call at 5:19 a.m. on May 18 and battled the blaze for an hour and a half before it was put down.

Jim Covino and his two daughters were awoken by the smoke detectors and originally thought the alarm was false. Jim told on-scene firefighters once he smelled the smoke and saw the fire coming from the front doors, that's when he retrieved his 9- and 13-year-old girls and escaped without any injuries.

Jim and his wife opened the Black Horse Tavern in August 2010. Covino is a retired Winchester police officer.

The original report and investigator's notes are attached in a PDF.