A woman, Doris Gillespie, was burned alive in her NYC apartment building on Saturday night after a man trapped her in an elevator, covered her with accelerant and set her on fire while surveillance camera caught the entire incident on video.

New York City Police spokesman Paul Browne said an unidentified man ambushed the 64-year-old woman as the doors of the elevator opened at the fifth floor of the apartment building in Brooklyn in Prospect Heights.  Browne said the woman was sprayed with accelerant and set on fire with a Molotov cocktail.

It was apparent he knew she was on the elevator, he said, adding the assailant knew the woman though would not release details about the motive.

The incident, at 4 p.m. on Saturday, was caught on two cameras in the building, one which was inside of the elevator. The man was dressed posing as an exterminator in a black jacket, surgical gloves and a white dust mask on his head. He was holding a canister with a nozzle he used to spray, according to images released by the New York City Police Department.

So far, police are still searching for the suspect and no arrests have been made.

Video footage showed Gillespie, who had just returned home from grocery shopping, attacked by the man. Police said she crouched and hid in the back of the elevator as the man sprayed the chemical directly in her face and sort of methodically, police said, over her head and her body.

Police said the man lit a rag in a bottle on fire using a barbeque lighter, let it burn a few seconds, before using it to set Gillespie on fire. The man reportedly paused before exiting down the stairs of the building, determining whether or not to throw the bottle in the elevator with the woman being burned alive.

Neighbors said the elevator and building was full of smoke when the reported a fire in the building, though they did not know initially know Gillespie was being burned alive inside the elevator. Residents reported hearing screams and saw smoke coming from the elevator and realized a person was inside.

Myself and someone from the sixth floor went down knocking to get people out. Knocking on doors telling people 'There's a fire, get out, get out, a resident named John told CNN affiliate WCBS.

Residents were evacuated from the building for six hours on Saturday evening.