A Weston couple say a man's threatened to kill them in a seemingly random confrontation.

Bob Hill's told Nova News he and his wife were 'terrified' by their ordeal at about 11-30 yesterday morning - during which the man seemed to be reaching for something in his back pocket, which he later threw under a car.

Bob says the offender first approached them as they walked into town over Hildesheim Bridge:

CLIP

B/A: Police say a man in his twenties has been arrested on suspicion of pubic order offences.