A weapon used in a number of unsolved murders has been discovered on display in the Imperial War Museum.
A VX58 assault rifle on show in a cabinet at the London museum was found by investigators re-examining paramilitary murders in Northern Ireland, BBC Panorama has reported.
The weapon was used in an attack on a Belfast betting shop in 1992 which left five Catholics dead, including a 15-year-old boy, as well as being linked to the killing of two men in 1998.
Although the weapon was originally recovered in 1992 and tests carried out to link it to the murders, officers from the Historical Enquiries Team (HET) could not find it when the case was reopened.
Families had believed that the gun was disposed of after the initial case was closed.
It was, in fact, on display as part of the Imperial War Museum’s (IWM) exhibit on the Troubles.
The rifle has now been sent for further tests.
The museum said that it was given the weapon by the Royal Ulster Constabulary Weapons and Explosives Research Centre.
A spokeswoman told the BBC: "IWM believes that we provide an appropriate context for the display of items used in conflict. This object has always been displayed in the context of a wider story which sets it against other items from both sides of the Northern Ireland conflict."
She added that the museum was aware that the gun had been used in “specific events” but was given no further details.
The IWM is now investigating if any other weapons in its collection were used in unsolved murders, alongside the police ombudsman.
Billy McManus was one of those murdered in the attack on the betting shop on the Ormeau Road, and his son Willie was appalled at the discovery.
He told the BBC: "I am absolutely shocked that a gun connected with so many deaths was there on display for anyone to come and see at the Imperial War Museum in London. It should be here in a secure place so that it can be used for ballistics.
"Why would somebody let something so important be shipped to England to be put on display? What does that say about their treatment of the case? They just don't care."
A police ombudsman investigation into the weapon’s history will now take place.
Assistant Chief Constable Will Kerr said the Police Service of Northern Ireland would fully support this.
He said: ”I have been made aware that investigators from the Police Ombudsman's office have recovered a weapon on loan from police in Northern Ireland to the Imperial War Museum in London as part of a permanent exhibition relating to 'the Troubles'.
“In the interests of public confidence and transparency, I accept that it merits further investigation."