A body of a man suffering from 'head injuries' was found at a mid-terraced house in central Blackpool, police said.
The 63-year-old was pronounced dead after emergency services were called to Clinton Avenue at around 2.15am on Monday, police said.
One neighbour, who did not wish to be named, said she heard 'arguing and shouting' at around 12.30am, and added: "They were slamming doors and swearing."
She said it 'went quiet' before the row continued a short time later.
READ MORE: Identity of Blackpool 'murder' victim revealed as neighbours tell of shock and 'shouting' inside home
She added that a man was seen lying on the ground in the back garden that night while another urged him to 'wake up'.
Details of the death, which was being treated as 'suspicious' by police and led to a man, also 63, being arrested on suspicion of murder, were only made public today.
One witness said police officers and forensic experts have been going in and out of the house since, with a tent put up in the back yard.
A post-mortem examination has been carried out but failed to offer murder squad detectives a definitive cause of death, The Gazette understands, with an investigation continuing.
Police officers were stationed at the front and back of the home this afternoon, while detectives carried out enquiries with neighbours.
There was no tent in the garden this afternoon, though wet clothes, an old exercise bike, and scattered plastic boxes could be seen.
The back door's window pane had been smashed, repaired with black tape, while at the front of the house, net curtains hung in each of the windows.
In a statement, Lancashire Police said: "We were called around 2.15am on Monday, January 15, following reports of a sudden death in Blackpool.
"Officers attended an address in Clinton Avenue where a 63-year-old man was found with head injuries.
"He was sadly pronounced dead at the scene.
"The death is currently being treated as suspicious.
"A 63-year-old man has been arrested on suspicion of murder and is currently in custody."
A spokeswoman for the North West Ambulance Service (NWAS) said a senior medic and ambulance were called to the street, which runs off Ashton Road and parallel to Park Road, at 2.19am. The first arrived at 2.24am.
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