A 21-year-old man is recovering in hospital after being attacked outside a popular Huddersfield bar in the early hours of Sunday.
Det Insp Ian Mottershaw, of Kirklees CID, said it was uncertain where the incident had begun but it had ended in the man being attacked outside Verve bar on Byram Street at 2.30am.
Mr Mottershaw said: “We are still trying to establish what occurred and are working with witnesses and CCTV to piece together what has happened.
“What we do know is that a man has suffered serious but not life-threatening injuries to his stomach.”
He said there was a possibility that the injury had been caused by a stab wound.
This latest act of violence comes hard on the heels of two other violent attacks in the town centre on a Saturday night.
Two weeks ago a man was stabbed in the back as he tried to help a woman in Huddersfield town centre . Two teenagers have appeared in court.
And on the same night a 22-year-old man from Lowerhouses was stabbed in the stomach in Tokyo nightclub in Queen Street. He had to be taken to Leeds General Infirmary for treatment.
Anyone who is able to help police with their enquiries should contact Kirklees CID on 101.
In unrelated investigations, police would like to speak to the people pictured in the image gallery below. The people pictured in the images may be witnesses as well as suspects. If you recognise anyone, contact police on 101 quoting the reference number on the image caption.