A man, aged in his 60s, has been taken to Southmead Hospital in Bristol after being stabbed in Warminster.
It happened just after 1030am yesterday in Portway.
Police say initial investigations suggest it followed an altercation with someone known to the victim.
They're looking to hear from anyone who saw a man running away from the scene.
The man's condition is described as 'stable'.
Detective Sergeant Kerry Lawes said: “We have spoken to neighbours and people who know the victim, and the suggestion is that he had an acquaintance in the address at the time of the incident.
“We believe he is known by the name of Rob or Robert and he has been described to us as a white man, in his 30s, around 5ft 10ins tall and of stocky build.
“He is believed to have been sleeping rough in the Warminster area recently.
“If you recognise this description or you believe you may know who this person is, then please contact us urgently.
"We would also like to hear from anyone who saw a man who was wearing just boxer shorts and no other clothing, in the Portway area shortly after the incident.
"If you saw him and know which way he went, this could be immensely important to our investigation.
“I would like to reassure the public that this assault appears to involve two people who are known to each other and there is nothing to suggest there is any wider risk to anyone else.
"Anyone with information should call CID on 101, quoting log 113 of today (25/08/19). Alternatively you can call Crimestoppers anonymously on 0800 555111."