Gwent Police are appealing for information after a man in his sixties was stabbed in the hand in Energlyn, Caerphilly.
The man was stabbed through the window of his car, suffering an injury that required stitches.
The incident took place on Wednesday, December 5 between 7pm and 7.30pm.
The attacker had two other people with him. They have all been described as white teenagers who were on bikes without lighting.
PC Lloyd, who is leading the investigation, says: “This was a completely unprovoked attack on a member of the local community which has left him with an injury that required hospitalisation.
“I’m appealing directly to the local community to come forward with any information or any witnesses to come forward that can help bring the perpetrator to justice.
“I would also appeal directly to the parents of youths in the local community to take a moment to consider where their children may have been that particular evening.”
Anyone with any information relating to this incident is asked to call Gwent Police on 101, quoting log number: 429 08/12/18