Business owners and store clerks say that they are still on edge a week after a deadly gas station robbery in Edison.

No arrests have been made in the Dec. 20 robbery at the Speedway Gas Station that left 38-year-old clerk John Bertram dead.

Business owners in the area say that they are taking precautions to protect their employees. The 24-hour Dunkin’ Donuts on New Brunswick Avenue in Edison posted a sign on the door stating that the shop will be closed from midnight until 4 a.m. daily. A cashier inside tells News 12 New Jersey that this is a result of the gas station robbery.

The Wawa on Woodbridge Avenue also posted a sign stating the store would be closed from 12 a.m. until 5 a.m. News 12 contacted the corporate office for comment about the reason for the new hours, but did not hear back.

RELATED: Suspect in deadly Edison gas station robbery remains at large

The Middlesex County Prosecutor’s Office says that the investigation is still ongoing.

But authorities in Suffolk County, New York, are investigating if the Edison robbery is connected to robbery at a shop in West Babylon on Long Island that happened hours before.

“The Suffolk County Police Department has been in contact with our law enforcement partners in Edison, New Jersey. Our agencies are aware of the similarities in the armed robberies and we will continue to share intelligence,” a spokesperson said in a statement.

In both robberies the suspect is seen wearing light-colored jeans, a hoodie, a black mask and gloves.

Anyone with information is asked to call Detective Loren Long of the Edison Police Department at 732-248-7531, or Detective David Abromaitis of the Middlesex County Prosecutor's Office at 732-745-4436.