Mark Noke, 64, died of a stab wound to his chest at his home in Warburton Road, Thornhill, in the early hours of Saturday, 25 February.
At 11.30am yesterday (15 March), in Queensway, Southampton, a 39-year-old Southampton man was arrested on suspicion of assisting an offender.
He has been bailed while enquiries continue.
Six other men, aged 21, 23, 28, 31 and two aged 20, have been arrested on suspicion of murder and bailed as part of the case.
DI Elizabeth Brunt said:
“We continue to follow up multiple leads and work through a large amount of evidence as part of our investigation into Mark’s murder.
“Please continue to report any information which could help bring those responsible to justice.
“Extra patrols continue in the Thornhill area so if you see an officer in the area and have any concerns, please speak to them.”
Anyone with information can call 101 or report via their website, quoting Operation Hibiscus or the crime reference number 44230077698.