Grange Villa murder: Stabbing victim Mark Shaw 'savagely beaten'
A man whose body was found tied up in a house in County Durham was savagely beaten and died of a single stab wound.
Mark Shaw, 29, was found after a passing beat officer became suspicious and forced their way into a house in Grange Villa near Chester-le-Street.
Three men aged 18, 19, and 22 and a 19-year-old woman have been arrested on suspicion of murder.
Mr Shaw's family said they were devastated by his death, which police said followed a "prolonged attack."
Mr Shaw, known as "Sharkey" was found in a bedroom at the house in Pine Street, where he lived, on Saturday.
No-one else was in the property at the time and it is believed those involved were known to each other, police said.
Two other people have been arrested in connection with the case - a 25-year-old man was released with no further action and an 18-year-old woman arrested on suspicion of assisting an offender has been bailed until the end of February.
Mr Shaw's mother Valerie Watson said: "Not only have I lost a son but Mark's sisters have lost their much-loved brother, and his 11-year-old son has lost a father.
"We have been left devastated by Mark's sudden death, but we have been overwhelmed by the generosity and kindness shown to us by so many people.
"I would urge anyone who has information to come forward and speak to the police so they can bring to justice those responsible."
Det Supt Adrian Green, of Durham Police, said: "The victim was subjected to what was a prolonged and vicious attack which lasted a considerable length of time.
"We believe this may have started in the house late on Friday night or into the early hours of Saturday, so I am appealing for anyone who may have heard sounds of a disturbance at those times to come forward.
"However, no alarm was raised until that evening when a local beat officer was made aware there might be someone at risk in the premises."
He said more than 60 police staff, including forensic experts and detectives, were working on the case.