Investigators in Tarrytown are trying to figure out what sparked a deadly fire inside a condo.

"They were just outside watching everything being destroyed," says Tarrytown resident Pat Hanson.

It was a sleepless night for Hanson and many of her neighbors off of Martling Avenue.

"What woke me up was the smoke, I smelled smoke. Then, I realized they broke all the windows to try and get at the fire," says Hanson.

Shortly after midnight Thursday, flames erupted inside a condo just across the path from where she lives.

That fire left a 77-year-old woman dead, according to authorities.

On top of the tragedy, several neighbors are dealing with the impact of the damage.

"The people can't stay there, they have no lights, they have no heat, they have no water. It has been shut off for the whole building," Hanson explains.

It's all coming during one of the coldest weather spells as the coldest air so far this season, races down with gusty winds.

Firefighters tell News 12 this is a busy time of year for them.

This week alone, they've already responded to at least four major fires around Westchester County.

There's no word on what caused the deadly fire in Tarrytown.

The identity of the victim has not been released.