Police divers investigating a murder have begun a three-day search of a Northampton lake.
David Brickwood, 74, was stabbed five times in his Lindsay Avenue home in Abington in September 2015.
Despite a number of arrests, no one has ever been charged with murder and no suspects or murder weapon have been found.
Now, police are searching Eastfield Park lake, roughly one mile from Mr Brickwood's address.
Detective Inspector Phil Mills said: "A team of seven divers will be systematically searching the lake over the next three or four days. We hope to find a potential murder weapon or any items that might have been taken from David's home.
"We are here as part of the investigation into the murder of David Brickwood, an elderly gentleman who was murdered in a brutal attack in his own home.
"This area is not too far from David's address. This is a potential location the offenders may have fled to and discarded any items they had."
"The difficulty is we are not entirely sure what we are looking for. We have never located the weapon that killed David and we don't know exactly what was stolen from his address.
"David was murdered 15 months ago. It's frustrating and challenging for us, and Northamptonshire police are doing everything they can to bring the offender to justice.
"Only time will tell what we find over the next three days."
"There has been nothing to suggest the offender is a danger to the public. There have been no replicated attacks since September 2015. We believe it was a tragic one-off incident."
“David was a popular and widely known local community member. He was a hardworking man who ran a business from home and regularly helped his neighbours."
Detectives believe Mr Brickwood was deliberately targeted with the offenders planning to rob him and going prepared to use violence.
Two Ford Focus cars seen near David’s house on the night of his murder have not been located. Anyone with information about these cars should contact the investigation team.
Six people have been arrested during the course of the investigation, but no-one has been charged and no-one is currently on bail.