Two men disguised themselves by donning burkas to carry out an aggravated burglary, police have said.
The pair entered a house in Dorothy Road, Leicester, at about 10:30 BST on Wednesday, and attacked the man who lived there.
They stole a safe containing cash, watches and other items before leaving in a van.
Leicestershire Police said they did not believe the raid was racially or religiously-motivated.
A video filmed by a neighbour and posted on Facebook appears to show the pair arriving at the house.
Det Con Nev Walker said: "We are keen to speak to anyone who was in the area at the time and saw the men entering the house, loitering in the area or making off in the van.
"Do you know where the silver van went next? Have you seen any abandoned clothing? Have you heard any rumours about who may be involved?
"Small details will help us piece together information and could prove vital in bringing those responsible for this incident to justice."