The man, who is in his early 60s, was taken to hospital with serious injuries.
At around 4.10 pm on Thursday 16 December, an ambulance attended a flat on Coleshill Road, after a man was found with injuries believed to have been caused by an assault.
The man, who is in his early 60s, was taken to hospital with serious injuries.
A 46-year-old man from Atherstone was arrested and is now on bail while enquiries continue.
Det Insp Gareth Unett, from Nuneaton CID, said: “Although we believe this incident happened inside a property, as part of our ongoing enquiries we would appeal to anyone who may have seen or heard anything suspicious in this area at the stated date and time to please come forward.
“A man is currently in hospital with serious injuries and we need to ascertain how these were sustained.
“We believe the incident may have taken place between late on the Wednesday evening (15 December) through to the Thursday (16 December) morning.
“Anyone with any information, no matter how insignificant, is asked to call Warwickshire Police on 101 quoting incident number 218 of 16 December 2021.”
National Secondary School Place Offer Day
Flooding hits after days of heavy rain
Children seeing dangling from Leicestershire railway bridge
Hinckley Lloyds branch to stay open until 2027
Bedroom furniture flytipped on country lane
Emergency animal rescues by firefighters in Leicestershire
National offer day - what it means for you
