Police believe two cash point robberies in which the victims were threatened with needles are linked.
Both took place outside the NatWest bank in Tisbury Road, Hove, early in the morning.
The latest happened at 6.35am last Thursday.
The victim was threatened with a hypodermic needle and ordered to hand over £200 he had just withdrawn.
The first robbery took place at 7.20am on April 25, when the victim was threatened with a brass needle and forced to hand over £20.
Inspector Michelle Collins said: "Detectives are investigating a possible link.
"We would advise people to take extra care when making cashpoint withdrawals, especially early in the morning.
"If possible they should use them when there are plenty of other people around and should always be aware of who is behind them.
"If they have to go to a cashpoint early in the morning or late at night they should try to do so with somebody they know for extra security."
Anyone with information about the robberies should phone Hove police station on 0845 6070999.
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