A 26-year-old man known as "Boston Rob" has been arrested after confessing to robberies in suburban West Palm Beach while armed with a needle-tipped syringe.

Robert James McCullock is being held at the Palm Beach County Jail without bond. He is facing four counts of robbery. He is homeless, records say.

The Palm Beach County Sheriff's Office arrested McCullock on Wednesday afternoon after he was identified as the man who committed a noon robbery at the Cellular Express phone store at 122 N. Military Trail.

Two store employees said McCullock walked in, demanded money and said he had a gun. McCullock then walked up to an employee and held out the syringe. A manager opened the cash register and gave McCullock about $700.

McCullock was found nearby in the Southern Pine Estates neighborhood after deputies set up a perimeter and searched for him. He was taken into custody.

While being questioned, McCullock allegedly confessed to committing the crime. The investigator also asked about three more robberies — of a Subway restaurant and the Four Seasons Hair Salon; of a person on South Military Trail on Monday.

McCullock allegedly confessed to all three robberies and provided specific details "to the incident which he would be the only person to have knowledge," a sheriff's report said.

McCullock confessed to using the syringe during the robberies of the salon and the person, the report said.