Cops: Man holds up Shirley discount store at knifepoint

Police are investigating an armed robbery at a Shirley discount store on Sunday night, authorities said.

A man with a knife demanded cash from a clerk at Island Dollar at 579 Montauk Highway around 6:30 p.m., a Suffolk County police spokesman said.

The clerk handed over the money and the man fled, police said.

The department’s Seventh Squad detectives are investigating the holdup.