A dog walker was threatened by a man who approached her from behind with a knife.
The woman victim was walking her dog in Lake Lane, Barnham, when a man with his own dog threatened her on Sunday June 22 between 8.45pm and 9pm.
The occupants of a passing car shouted at the man and the woman and her dog ran way to safety without injury.
The suspect is described as a white, in his fifties, with grey balding hair, wearing jeans and a t-shirt.
PC Jill Peacock said: "It seems the dogs, which were both on leads, had barked at each other, but that doesn't account for what happened next. We are seeking any further witnesses to this incident and anyone who can help is asked to contact us via 101 or email firstname.lastname@example.org serial 1254 of 22/6."
A 52-year old local man was arrested on suspicion of possessing a knife in a public place and after being interviewed was released on police bail until July 14 while enquiries continue.