NEW YORK - The NYPD is hoping surveillance video will lead them to the person who attacked and robbed a man with a walker in Harlem.

The clip shows the robber holding the door open for the 61-year-old victim in an apartment building near Manhattan Avenue and Saint Nicholas Avenue on Monday afternoon.

He then snatches a gold chain from the victim's neck and knocks him to the ground before running away.

Anyone with information on the case should contact the Crime Stoppers hotline at 1-800-577-TIPS, or text CRIMES and then enter TIP577, or visit www.nypdcrimestoppers.com.