CARLE PLACE, N.Y. (CBSNewYork) — Police are investigating whether an armed robbery at a Long Island store where the suspect dressed as a custodian is part of a violent pattern of crime.

As CBS2’s Jennifer McLogan reported, juts before closing a man using a broom and wearing a bright green work vest walked into the maternity store in Carle Place.

With his head down, the man appeared to be a custodian until he turned around and workers saw his face was concealed behind a mask. Then, he pulled a gun.

The robbery forced employees to the back of the store, bound their hands behind their backs with zip ties and grabbed cash from the register and safe. The robber then fled the scene.

The workers were able to free themselves and call 911.

Shoppers said the robbery makes them nervous.

“Oh my God, that’s terrible. I shop there,” said Jody Mora.

Police in Nassau and Suffolk counties are investigating whether the robbery is part of a violent pattern of customers and store employees being tied up by a thin-built, 6-foot-tall suspect.

So far, all the stores targeted have catered to women. Police said in all of the robberies, the suspect has hidden behind a dark mask, displayed a gun and tied the wrists of the victims.

Among the stores in strip malls that have been hit are Joyce Leslie in Carle Place; a Mandee clothing store on Hempstead Turnpike in East Meadow; a New York & Company on Montauk Highway in West Babylon; and a Rainbow clothing store on Wellwood Avenue in Lindenhurst.

“People are terrified. You think you’re shopping and you’re taken off guard. It’s scary,” said shopper Jocelyn Zeller.

Police are urging residents that if they ever find themselves in a robbery situation to remain calm and comply with demands.

“Be the best witness possible. Get physical descriptions, note how the suspects speaks, description of the weapon being used — critically important as is the how the person flees the scene,” said Suffolk County Police Det. Lt. John Rowan.

Victims at the maternity store said they’re unsure if there was a getaway car, but the parkway entrance is just down the road.