The 20-year-old was killed at his sister's home in Clifton Mount, Harehills, Leeds.

It is now thought the 9mm round was fired from a converted Baikal gas handgun which is designed to fire blanks or tear gas pellets and is a favourite with gangsters in Britain.

Mr Chadwick was shot in the head on June 24 by one of three men who burst into his sister Gemma's home. Detectives say

Mr Chadwick, the father of a three-year-old daughter, may have been a victim of mistaken identity or it may have been a robbery which went wrong.

Last week Baikals featured in a court case in which seven men were jailed for their part in the UK's biggest gun running operation.

The men, from West Yorkshire, Greater Manchester, Merseyside and Essex, were part of a gang importing and converting the guns from Lithuania.

Police seized 56 guns and 856 bullets but it is believed many more are in circulation.

The guns, described as "ballistic bling" became a status symbol among street gangs and have been used in crimes in Leeds, Bradford, Manchester, Liverpool, Sheffield and Scotland.

The guns can be bought legally for £140 in Lithuania, but they are then stripped down and re-barrelled to fire 9mm bullets.

Imported into Britain, the weapons change hands for around £2,500.
Baikals are popular among criminals because they are small and, unloaded, weigh just 2lbs

A Baikal gun has been used in a number of British killings including those of two teenagers in London and one in Sheffield.