A couple were attacked in their car in Pett Level on Monday (July 8).
The man and woman had to shelter in their Citroen C3 car when the assault took place in Pett Level Road at 4.15pm.
Police said the man who attacked the couple was thrusting a knife at them through the windows of the car.
Detective Sergeant Tony Webb said: “We are seeking any witnesses who observed the incident or the build up to it. The man is known to the couple and there was an incident beforehand that led to this attack.”
Anyone who witnessed the incident is asked to call 101 quoting serial 1174 of 08/07. Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.