Police forensics experts are examining a gun or replica found dumped in a rubbish bin in Lan Kwai Fong early yesterday.
Officers refused to speculate whether or not the weapon might be linked to Tuesday's raid in Tuen Mun, in which two robbers carrying a handgun and an axe intercepted two security guards and stole a cash box containing $690,000. One robber fired a shot at police.
'It is a pistol-like object,' a police spokeswoman said. 'We still do not know whether it is genuine or not.'
She said a 49-year-old woman found the object wrapped in a plastic bag at a refuse collection point and reported it to police at 4am.
Forensic experts are conducting tests on the weapon. Analysis of a bullet from the scene of the robbery in Tuen Mun showed it to be from a .38 calibre revolver - the same as those used by police.
The spent round is being checked to see whether it was fired from a missing police gun or other weapons used in previous shootings.