Police were called at 3:56am this morning (8 April) to reports of a man who was injured.
Emergency services attended a property on Fell Lane in Keighley and found a man in his 40s with a serious injury.
He was taken to hospital but was pronounced deceased a short time later.
One woman and two men have been arrested on suspicion of murder in connection with this incident.
A large police cordon is currently in place whilst officers continue with their enquiries.
Anyone who witnessed anything in the area, or has any further information is asked to contact the police via 101 quoting crime reference number 13210171973 or information can be passed to Crimestoppers on 0800 555 111.