The star witness in the case against former police inspector David Gatt was boarded out from the police corps five months ago, the court heard yesterday.

Police Constable Mario Portelli, who became known by his police number PC99, is the prosecution’s main witness against Dr Gatt, who stands accused of being the mastermind behind a string of high profile hold-ups.

Assistant Police Commissioner Mario Spiteri, who is stationed at the police human resources department, confirmed in court that Mr Portelli had been boarded out.

A board composed of three doctors accepted the medical reasons submitted for Mr Portelli’s boarding out.

Magistrate Tonio Micallef Trigona ordered Dr Spiteri to produce the medical file at the next sitting.

Dr Gatt is accused of being behind the hold-up at HSBC headquarters in June 2010 and another on a jeweller in Attard that December.

He is also accused of masterminding the 2007 heist on the HSBC Balzan branch when €1 million was stolen.

Mr Portelli testified in previous sittings that Dr Gatt was behind the robberies.

The defence had queried whether Mr Portelli had ever been held at Mount Carmel Psychiatric Hospital, which he had denied.

Lawyer Joe Giglio is appearing for David Gatt.

Police Inspectors Joseph Mercieca and Michael Mallia are prosecuting.