A fourth person has been charged with murder following the death of a man in a suspected ammonia attack, police have said.
Andy Foster, 26, was injured in the alleged incident when he opened the door at an address in Eighton Terrace in Wrekenton, Gateshead, on 20 August.
He later died in hospital.
Three men have already been charged with murder and remanded in custody.
Officers made two further arrests on Friday and, on Saturday, charged Yousef Wynne, 39, of Wuppertal Court, Jarrow, with Mr Foster's murder.
He has been remanded in custody and is due to appear before South Tyneside Magistrates' Court on Monday 13 November.
A 24-year-old woman arrested on suspicion of assisting an offender has been released on bail.
Senior investigating officer Detective Inspector Tam Fowler, of Northumbria Police, said: "Andy's family are still coming to terms with what has happened, and we are continuing to support them in any way we can.
"The public have been very supportive of our efforts so far and I hope our continued work and further arrests show just how seriously we are taking this incident.
"Our investigation remains ongoing and we are still keen to hear from anyone with further information which could help us get answers for Andy's loved ones.
"Once again, I would ask that the public stays away from any speculation or social media commentary, as this may jeopardise the live legal proceedings."