One of the men being questioned in connection with the murder of a man in Downham Market initially left the scene in handcuffs, as police gave CPR to the victim.
Officers had been called to a property in the town's Bulrush Avenue at around 8.12pm on Sunday following reports of a disturbance there.
When they arrived they found a 39-year-old man with serious head injuries.
Two men, aged 47 and 22, were detained and handcuffed while officers gave CPR to the injured man until paramedics arrived at about 8.30pm.
Despite their efforts, the man was pronounced dead at the scene.
At around 8.20pm, the 22-year-old detained man left the property.
He was arrested at 10.26pm at an address in Paradise Road, around 400 metres away.
Police have launched a murder investigation and both men were taken to King's Lynn Police Investigation Centre for questioning.
Earlier today, police were given more time to question the pair.
A spokesman for Norfolk police said: "We can confirm that one of the suspects detained at the scene in the Bulrush Avenue murder investigation left the scene after being handcuffed and was arrested at another property a couple of hours later."
The spokesman said officers had been faced with "a challenging scene" when they arrived at the Bulrush Road address.
They added: "Protecting and saving life is at the core of every officers’ operational duties, and officers at the scene made the decision to prioritise treatment to the injured man, who despite the best efforts of both police and paramedics, was pronounced dead at the scene."
Meanwhile, Downham Market mayor, Jenny Groom, commended officers for their response on Sunday night.
She said: "I believe the situation that the police who attended were met with was really quite horrific, all credit to them because they did their best in a really difficult and horrible situation.
"My thoughts go out to them and to the families involved."
A Home Office post-mortem examination will be carried out today to establish the cause of the death.
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