A man has been arrested after a 26-year-old woman died in the early hours of the morning in Halifax.
Police were called at 2.16am on Sunday to Silver Street in the centre of Halifax.
A woman had been left unconscious following what police have described as an 'altercation'.
She was taken to hospital by ambulance but was pronounced dead a short time later.
A 26-year-old man has been arrested on suspicion of murder and remains in custody.
A post mortem examination is due to be conducted later today.
A large section of the town centre is cordoned off as police undertake forensic examinations of the area.
The roads affected are Waterhouse Street from the junction of Crossley Street to the junction of George's Square; Silver Street and Crown Street, according to Calderdale Council.
Anyone who saw what happened or who has any information that could help the investigation is asked to contact West Yorkshire Police Homicide Major Enquiry Team via 101 quoting Operation Patondeat.
Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.