A man has been arrested on suspicion of murder.
Emergency services were called to White Horse Yard, in Wakefield city centre, just before 9.30pm on Thursday night.
A 47-year-old man had been found unconscious but despite the efforts of paramedics and police officers who tried to save him he died later.
Detectives have arrested a 53 -year-old man in connection with the incident.
Detective Chief Inspector Elizabeth Belton, from West Yorkshire Police’s Protective Services (Crime), said: “At this stage we are treating the death as suspicious and have a 53-year-old local man in custody.
“He was arrested from the scene last night and is being held on suspicion of murder.
“The investigation is at an early stage and I would ask anyone who may have been in Wakefield city centre around of the time of the incident and seen anything suspicious to contact police.
“Neighbourhood officers are in town to reassure local people and while these type of incidents understandably cause concern I do not believe there is any wider danger to the public.”
Anyone with any information should contact police on 101 or Crimestoppers, anonymously, on 0800 555 111.