A Brooklyn man has pleaded guilty to fatally burning an elderly woman inside the elevator of her Prospect Heights apartment building.

Prosecutors announced Wednesday that Jerome Isaac had pleaded guilty to first-degree murder, arson and torture in the December 2011 death of Deloris Gillespie in Brooklyn.

The plea bargain calls for a sentence of 50 years in prison.

Prosecutors say Isaac attacked the 73-year-old woman because he believed she owed him money. They say he doused her with gasoline, lit her on fire and then threw a firebomb inside the elevator.

According to statements Isaac made to police, he said Gillespie "owed me some money for some work I did for her. I told her to give me $300. I was cleaning up her apartment for about four or five months and she never paid me."

The attack was recorded on a security camera. Isaac is scheduled to be sentenced on Nov. 30.