The high profile case against former Police Inspector David Gatt, now a lawyer, was dented yet again yesterday by defence lawyers who called into question the credibility of the star witness.

This was the second time that the evidence by PC Mario Portelli was challenged. Defence lawyers Joseph Giglio and Edward Gatt yesterday summoned a firearms dealer to prove a point they wanted to make.

Dr Gatt is pleading not guilty to being involved in the theft of more than €1 million from a Balzan bank in 2007, the failed heist on HSBC’s operations centre in Qormi that ended in a shootout with the police in June 2010, the failed attempt to break into a security van carrying about €2.8 million in cash last year and the attempted robbery of a jeweller in Attard in December 2010.

The defence team pointed out that PC Portelli had testified that Dr Gatt had showed him a Ruger revolver in April 2010, held it to his head and said: “Enter the dragon”.

The lawyers argued that the incident could not have happened as described by PC Portelli. At the very least, it could not have involved the firearm described by the witness if the incident did occur on the date indicated.

Firearms dealer Stephen Petroni testified that the gun in question, a Ruger GP-100, 357 Magnum, was bought by Dr Gatt on June 20, 2010 through Obelisk auctioneers.

Mr Petroni said he received the weapon from Germany on May 26 and held it until he received the necessary documentation from Dr Gatt, which was standard practice. He gave the firearm to Dr Gatt on July 5, 2010.

Mr Petroni will be shown a photograph of the revolver, which the police say was seized from Dr Gatt’s apartment during a raid, in a later sitting so he will be able to ascertain conclusively that it is the same the gun. When PC Portelli had positively identified the gun he had done so on the basis of a picture that also listed its serial number and that matched the one in Mr Petroni’s records, the lawyers said.