A New York City man was arrested and charged with murder after allegedly burning an elderly woman to death inside her apartment building elevator over $2,000 he claims she owed him.

Authorities said that when 73-year-old Deloris Gillespie went up the elevator to her fifth-floor Brooklyn apartment on Saturday, carrying groceries, suspect Jerome Isaac was waiting.

Surveillance video from inside the small elevator shows 47-year-old Isaac looked something like an exterminator, with a canister sprayer, white gloves and a dust mask, which was perched atop his head like a pair of sunglasses. The sprayer was full of flammable liquid.

When the elevator opened Saturday afternoon, the suspect sprayed the woman, who turned around and crouched down to try to protect herself, New York Police Department spokesman Paul Browne said. The attacker sprayed Gillespie in the face and continued to spray her "sort of methodically" over her head and parts of her body as her bags of groceries draped off her arms, Browne said.

Then, Browne said, the attacker pulled out a barbecue-style lighter and used it to ignite a rag in a bottle. He waited a few seconds as Gillespie huddled on the floor. Then he backed out of the elevator and tossed the flaming bottle in.

Neighbors in the Prospect Heights building quickly reported a fire, but had no idea that a woman was being burned alive.

Isaac, reeking of gasoline, went into a police station overnight and implicated himself in Gillespie's death, Browne said. The suspect told police he set her on fire because she owed him $2,000 for some work he had done for her, Browne said.

Isaac appeared in court Monday with visible burns on his face and said nothing. He was held without bail. His lawyer requested solitary confinement and medical attention and did not speak outside court.

Jaime Holguin, who lives on the same floor as Gillespie, saw surveillance pictures of the attacker and said, "Oh, my God!"

Holguin, the manager of news development for The Associated Press, said the attacker looked like a man who lived with Gillespie for about six months last year and appeared to have been helping her out.

That arrangement apparently ended by early 2011, but months later Holguin started seeing the man nearby on the street, looking "a lot more disheveled."

Gillespie's nephew, Rickey Causey, told Fox affiliate WNYW-TV that his aunt had hired Isaac to do odd jobs around her apartment but fired him after she caught him stealing.

"He was doing more stealing than cleaning," Causey told the station.

Causey said the suspect had left a note on Gillespie's door with a list of chores for which he was demanding payment, according to the station.

Browne said that after setting Gillespie ablaze, Isaac set another fire at his own apartment building nearby, then hid on a roof before turning himself in to police.

Isaac was arrested Sunday on first-degree murder and arson charges.

Residents were evacuated and kept away from the six-story building for hours Saturday night as police investigated. On Sunday, Holguin said, the fifth floor was a mess, with a melted elevator door and a layer of water on the floor.

Holguin said he and his girlfriend had taken the elevator on their way out of the building shortly before the attack. They didn't see anyone on the floor with them but did notice an odd smell, as if someone was painting, he said.

Holguin said police told them later that the assailant was already in the building and perhaps had hidden on another floor when they left their apartment.

The Associated Press contributed to this report.