A murder investigation has been launched after a man died following an assault outside a pub. 

Police have arrested a man on suspicion of murder following the serious assault outside the Red Lion pub in Dereham on Saturday evening.

On Sunday morning, paramedics attended the victim’s home, at around 5am, after he became unwell.

The man in his 30s was then taken to the Norfolk and Norwich University Hospital where he died on Sunday evening.

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Police became aware of the death on Tuesday and an investigation led back to the serious assault outside the Quebec Street pub.

The incident outside happened by the Red Lion in Quebec StreetThe incident outside happened by the Red Lion in Quebec Street (Image: Google)

The victim and attacker are believed to be known to each other.

Police arrested a man in his 40s on suspicion of murder on Wednesday, at the Beeston Ploughshare pub seven miles away.

A witness who saw the arrest said: "A guy came in and had a pint of Guinness, drank half then went to the loo.

"Police arrived shortly after where they handcuffed him then arrested him on suspicion of murder, it was all very surreal."

He was taken to Wymondham Police Station, where he remains.

It is believed the Red Lion pub has been closed since yesterday following the assault. 

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Supt Sonia Humphreys said: “We understand our communities will be concerned by this incident and people may see more police officers in the town as we conduct our inquiries.”

A Home Office post-mortem is due to take place today to understand the nature of the death.

Police are now appealing to the public for witnesses and anyone who may have information about the attack.

Anybody who may have information should contact the Major Investigation Team quoting reference 36/52076/24.