The Massachusetts fire marshal has confirmed the cause of a fire that killed five people last weekend in the Franklin County town of Warwick.

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Fire Marshal Peter Ostroskey said he’s not sure exactly how, but fire escaped from a wood stove in the kitchen and spread to what he calls “nearby combustibles.”

“I believe it was wood and some of the finishes around the wood stove,” Ostroksey said in a phone interview.

In addition to Warwick’s volunteer fire department, 16 others helped fight the fire early Saturday.

With no hydrants, trucks had to fill up at a pond 1/3 mile away and drive the water back. And because this was a narrow dirt road, the trucks then had to drive into New Hampshire to loop back to the pond. It took 45 minutes.

Still, this was a hard one from the start, according to Ostroskey.

“It’s fair to say that the house was heavily involved in fire at the time of arrival of the fire department,” he said.

Five people died: Lucinda Seago and four of her children. The father — Scott Seago — and one child escaped.

2017 Fire Deaths

The fire marshal earlier this week announced the cause of a fire early Monday in Milton that killed two elderly men, including Kenneth Guscott, the former head of the Boston NAACP. That blaze was caused by a space heater that overloaded an extension cord.

Combined, the Warwick and Milton fires left seven people dead. That puts fire deaths in 2017 well ahead of the average from recent years.

Since 2012, the state has averaged about 16 fire deaths during the first three months of the year. So far in 2017 — there have been 20 confirmed deaths, with three weeks of March still to go.