Thames Valley Police is appealing for witnesses following an aggravated burglary in Severn Drive, Newport Pagnell.
At around 10.30pm on Monday night (5/3), four offenders forced entry to a property.
The house was occupied at the time by three people, a 62-year-old man, a 56-year-old man and a 56-year-old woman.
The offenders demanded money and then assaulted one of the occupants, the 62-year-old man, causing injuries to the head and back which required hospital treatment. He has since been discharged.
The offenders had knives and a metal pole.
An amount of cash was stolen from the property during the incident.
The offenders are described as four men, all with face coverings and spoke with Eastern European accents.
A light coloured vehicle was seen in the area at the time and police are trying to identify this vehicle.
Investigating officer, Detective Sergeant Adam Billingham said: “This is a concerning incident but I want to reassure the public that we are conducting a thorough investigation to find the offenders.
“We need the help of the public and I would urge anyone who saw anyone acting suspiciously, or with information in relation to this incident, to call us as a matter of urgency via our enquiry centre on 101.
“If anyone recognises any of the men from their description we would ask them to come forward.”
If you have any information relating to this case, please call 101 quoting reference '43180068243', or contact Crimestoppers anonymously.