The two-alarm fire that destroyed the top floor of a three-story home on Hidden Cove Road earlier this month started in the laundry room of the residence.

Bainbridge Island Fire Department Assistant Chief Luke Carpenter said an investigator hired by the homeowners’ insurance company determined the starting point for the fire, but the definitive cause of the blaze wasn’t found.

“The fire could have started in the dryer itself, but there was a really long run to the dryer vent out of the house, and those can clog up with lint,” Carpenter said.

“He couldn’t determine if the fire began in the vent pipe or the dryer itself,” Carpenter said.

Carpenter said the fire was investigated by the Bainbridge Island Fire Department and also the third-party investigator.

Such a tag-team approach is typical. Carpenter recalled that when The 122, a popular downtown nightclub, burned down last year, the department was joined in the investigation by other agencies, including the Bureau of Alcohol, Tobacco, Firearms and Explosives, and a private fire investigator.

“This was similar but on a much smaller scale,” Carpenter explained.

He said the finding by the third-party investigator — that the July 11 house fire originated in the laundry room — was consistent with what Bainbridge firefighters saw at the scene.

Firefighters saw flames coming from the second-floor laundry room when they went up the stairs to attack the fire, Carpenter said.

Carpenter, who is also fire marshal for Bainbridge Island, said homeowners should be aware that lint can easily accumulate in dryer vent hoses, especially those that are long or have elbows, and should regularly check and clean their dryer ducts.