Today (22 March) officers arrested a 25-year-old man from Southampton on suspicion of murder. He remains in police custody at this time.
A 39-year-old Southampton man had previously been arrested on suspicion of assisting an offender.
Yesterday he was rearrested on suspicion of murder and has been bailed while enquiries continue.
Mark, 64, died of a stab wound to his chest at his home address in Warburton Road, Southampton, on 25 February.
Acting Detective Chief Inspector Howard Broadribb is leading the investigation. He said: “New evidence came to light which led us to rearrest this individual.
“We continue to work through a large quantity of information and leads and I hope these arrests show the continued dedication our team has to getting justice for Mark and his family in what has been a complex investigation.
“We continue our appeal to find 23-year-old Leighton Tabone, who has links to Southampton and Gosport, as part of this case, so please call 999 if you see him. Anyone who is found to be harbouring him could be arrested for committing a criminal offence.”
Anyone with information can call 101 or report via the police website, quoting Operation Hibiscus or the crime reference number 44230077698.
Alternatively, you can contact the independent charity, Crimestoppers, anonymously on 0800 555 111.