A 32-year-old man arrested on suspicion of the murder of Shane Jones, 33, in Blackwood last week has been released on conditional bail pending further investigation.
Mr Jones died in hospital following the assault in Apollo Way on Tuesday, January 14.
A 35-year-old woman from Blackwood, who was arrested on suspicion of perverting the course of justice, has also been released on conditional bail pending further investigation.
Gwent Police say enquiries are still ongoing and have urged people with information to come forward.
Anyone with information can contact Gwent Police on 101, quoting reference 2000016470.
Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.