Man watching woman burn to death after setting her on fire

A man allegedly set a sleeping passenger on fire in a Coney Island subway train just before Christmas.

In a disturbing video, he is seen watching the flames engulf the woman who stood by the open door of the train.

A transit officer passed by but did not intervene.

The suspect, described as about 5'6" and 150 pounds, was last seen in a gray hoodie and dark knit hat.

Authorities are offering a $10,000 reward for information leading to his arrest.

Investigators believe he tossed a match on the woman while sitting across from her.