Police want to speak to three men in connection with a suspected firearms offence in Ford.
The men, described to be in their early 20s, were spotted walking along Ford Road towards the railway station at 2.15pm on Sunday September 2, according to police.
Police said one of the men was carrying, what was believed to be, a gun and the suspects were then captured on CCTV boarding a train to Littlehampton.
A police spokesman said: "One suspect is described as white, of slim build and with short fair hair. He wearing a blue hooded top with the number 72 in white writing on the front, white trainers, jeans and carrying a small blue Adidas bag.
"The second man was white, of slim build, with light brown hair and he was wearing a dark blue long-sleeved hooded top, a dark coloured puffer-style jacket and grey tracksuit bottoms.
"The third suspect was a white, of stocky build and with short dark hair. He was wearing a black Nike tracksuit with a white stripe down the arms and black trainers."
According to police, no other matters of this nature or linked to this incident were reported in this area at this time.
Police want to hear from anyone who was on the platform at this time or who remembers seeing these men.
Anyone with any information is asked to report it online or by calling 101 quoting reference 699 of 02/09.
Alternatively, you can visit the Crimestoppers website or contact the independent charity anonymously on 0800 555 111.