A CCTV image of the man who held up a Hove post office with a handgun has been released by police.
Detectives believe that he may have carried out two other robberies at the same post office inthe past three months.
Sussex Police said that the man escaped with more than £1,000 when he carried out the armed robbery at the post office in Melville Road, near the Seven Dials, last Friday morning (3 December).
The robber, wearing a balaclava, entered the post office at about 9.20am and threatened staff and customers, pointing the weapon at one woman.
The man then fled in a black Ford Mondeo LX with a white bonnet. Its registration number was P170 KVP.
The car was abandoned in Norfolk Road, Brighton, a short time after the robbery.
The thief then continued on foot west along Western Road, Brighton.
Police have recovered the car and a gun, which is being tested to confirm whether it is connected to the incident.
It is believed that the suspect bought the car in the few days before the robbery and it previously had legitimate owners from outside the Brighton area.
Detectives would like to hear from anyone who saw the car before the robbery, whether it was parked or was being driven.
They believe that the car may have been parked or hidden away for at least a week before this robbery.
The offender was wearing tracksuit bottoms with three white stripes down the side and a dark top with a light-coloured patch or emblem on his upper left arm
Detective Inspector Lee Horner said: “This is not a victimless crime.
“The staff at the post office are just like everybody else in the community trying to earn a living.
“They have been targeted three times now, which is naturally causing them huge distress, and we are very keen to catch this man to put their minds at ease.
“This man has used a very distinctive car, a dark Mondeo with a white bonnet, that he only had for a few days before this incident and he was wearing distinctive striped trousers.
“I am convinced that somebody close to him knows who this suspect is and I urge them to come forward and give us the information so we can put a stop to this man’s spree of offending before somebody is hurt.”
Two other armed robberies have taken place at the post office in the past three months – one on Thursday 23 September and one on Monday 4 October.
Detectives are looking into the possibility that the same offender committed all three.
Anyone with information is asked to contact Sussex Police on 0845 6070999 or call the independent charity Crimestoppers anonymously on 0800 555111.
