Three teenage boys were robbed in Hangleton Lane early on Saturday evening (19th November).
The boys, who are aged 13 to 14 and are from Portslade, were approached by three older teenagers at around 7.20pm and after asking for a light the suspects blocked their path, showed them a knuckleduster and demanded cash and mobile phones.
The boys handed over money before running away, while the suspects ran in the direction of Benfield golf course.
Police believe the incident was witnesses by two dog walkers, while an apparent girlfriend of one of the suspects spoke to the victims after the incident.
Detective Constable Leon Ryan said: “This will be upsetting news for local parents to hear of three young teenagers being robbed as they walked to a friend’s house, particularly as they were out as a group. We are doing all we can to find the suspects and inquiries are ongoing.
“A pair of dog walkers were seen walking on the other side of the road at the time of the offence and a girl, claiming to be the girlfriend of one of the suspects, asked the victims what the group had taken. I am keen to speak to them, as they may hold vital information in this investigation.
“With nights drawing in, it is even more important for everyone to follow simple advice to try and keep themselves safe. Walk in numbers and stick to well-lit and populated areas, make sure you plan your route before you set off and consider carrying a personal safety alarm.”
All three suspects and the girl have been described as being aged 18 to 19.
The first suspect is described as white, skinny, 6’3 and was wearing a black hoody and a black cap.
The second suspect is described as mixed race, skinny, 6′, had a shaved head and was wearing a dark blue hoody.
The third suspect is described as black, with large cheeks and nostrils, 5’9, stocky, wearing a dark cap with the peak angled up and a dark hoody.
The girl is described as slim, 6′, had shoulder-length blonde hair and was wearing a pink top under a white leopard print hoody, black leggings and chunky over the ear headphones.
Anyone with information is asked to contact Sussex Police on 101 or anonymously to the independent charity Crimestoppers on 0845 60 70 999.