Police are investigating a robbery late Thursday morning at Chase Bank at 4080 Nesconset Highway in East Setauket in which an armed man wearing a Darth Vader helmet and cape fled after receiving an undisclosed amount of money.

Police are still searching for the thief, who fled eastbound through the shopping center parking lot.

An eyewitness said the thief had a "young voice," as if he were in his late teens or early 20s, and was about six feet tall. She said the thief stashed the money in a drawstring backpack with a New York Yankees logo and ran after punching a muscular male customer who tried to intervene.