An assassin using a Soviet-era Makarov type gun shot IRA commander Gerard “Jock” Davison dead, the Police Service of Northern Ireland said on Tuesday.

The PSNI said the weapon and bullets used to shoot the 47-year-old former IRA gunman were of east European origin.

Det Supt Kevin Geddes, the senior investigating officer in the case, told BBC1’s Crimewatch the gun was “unusual” in the context of weapons normally used for close-range killings in Northern Ireland.

Mystery surrounds the killing of Davison in the Market area of central Belfast earlier this month. Within hours, the PSNI ruled out any republican dissident or Ulster loyalist involvement. Dissident republican prisoners held in the top-security Maghaberry jail outside Belfast even sent sympathy notices to a local paper.

Davison is believed to have either been personally responsible or ordered the deaths of up to 15 men from the early 1990s onwards. He is also accused of giving the order to attack Belfast man Robert McCartney that resulted in the Short Strand man’s death outside a city centre bar a decade ago.

Geddes told the Crimewatch programme: “The weapon and bullets used were an eastern European type called Makarov. These 9mm bullets are unusual in as much as they will not work in most types of western handgun. They are a slightly different size and can only be fired using a Makarov type gun.

“This type of weapon and ammunition are extremely rare in Northern Ireland. We have a photo of a Makarov type 9mm handgun which we are issuing. Someone knows about this weapon and its ammunition. We need people with information to come forward on the non-emergency police number 101.”

Geddes said: “The gunman is described by witnesses as being about 5ft 6in tall and was wearing a dark, hooded rain jacket. He made his escape from the scene up an alleyway towards Stanfield Place. We need to know where he went next. We are also issuing a photo of a similar type of jacket in the hope this may jog someone’s memory.

“We also believe the gunman may have been in the area some time before the shooting. A man fitting a similar description was seen standing at the junction of Welsh Street and McAuley Street at around 8.40am. A similar man was also seen with a red and white carrier bag, holding it with two hands on Welsh Street. They may be different people and they may be innocent members of the public. Either way, we need them to come forward so that they can be ruled out of our inquiries.”