Officers in Doncaster are appealing for witnesses after an assault in the Wheatley area last month.
At around 6.30pm on Wednesday 15 May, the victim, a 60-year-old man, was in his property on Chelmsford Drive when there was loud banging on his front door.
On opening the door, it is reported that four men entered the property and assaulted him.
The victim suffered serious head injuries and a ruptured spleen.
Enquiries are continuing and officers are now appealing for witnesses to the incident, or anyone with any information to contact them.
If you know anything that might help with the investigation, please call 101 quoting investigation number 14/76794/19.