Two women were being questioned on suspicion of murder today after a young man was found stabbed to death.
Police launched a murder investigation after the man's body was found at a house in Peterlee, County Durham, early yesterday.
Shortly before 3am, police and paramedics were called to an incident at a semi-detached house in Sledmere Close, where they found a 20-year-old man in the living room, covered in blood after apparently having received multiple stab wounds.
Despite efforts to revive him he was pronounced dead at the scene.
Two women, aged 24 and 20 were arrested at the house.
Officers from Northumbria Police, acting on behalf of their colleagues in Durham arrested a 19-year-old man at an address in Holywell Avenue, Walker.
He and the two women are being held on suspicion of murder and all three were to be interviewed by detectives from Durham.
A man and a woman were also arrested by Northumbria Police at the house in Walker on suspicion of assisting an offender.
They are in custody on Tyneside.
Much of Sledmere Close in Peterlee was cordoned off to allow a forensic examination of the scene to get under way and for house to house enquiries to take place.
So far the murder weapon, which is thought to have been a knife, has not been traced.
Around 30 detectives and other specialist staff are working on the case and an incident room has been established at Peterlee police station, under the supervision of the senior investigating officer, Det Supt Ken Donnelly.
Police were contacting relatives of the dead man, who is thought to be from the Walker area.
A post-mortem examination was expected to take place yesterday to determine a formal cause of death.
Det Chief Insp Steve Chapman said the cause of the incident was yet to be established but it was believed all those involved knew each other.
"We would be keen to hear from anyone who heard a disturbance or noticed anything unusual in the Sledmere Close area of Peterlee in the early hours of Sunday.
"Crimes involving bladed weapons are relatively rare in our force area, but sadly on this occasion it would appear a young man has lost his life in such a way."
Anyone with information should contact the incident room at Peterlee on 0345 6060 365 or call Crimestoppers on 0800 555111.