The gang, allegedly led by a 23-year-old Swedish citizen of Iranian origin, struck Sheikh Enterprises in Oslo’s immigrant-heavy Grønland district in broad daylight, keeping employees and customers at bay with an AK-47 machine gun.
According to Norwegian newspaper VG, four masked men stormed into the shop shouting “down”, “down”, then smashed the glass counters with crowbars, and began shovelling jewellery into their bags.
Moments afterwards, a fifth man arrives with the machine gun.
The group wore black balaclavas, ski goggles and identical uniforms of black trousers and black jackets.
They came prepared with protective gloves to avoid cutting their hands on the broken glass.
After the robbery, the men jumped into a black Audi with Swedish plates, which was waiting outside, and, after the shooting warning shots into the air from the weapon, sped away.
The five perpetrators were seized in Stockholm only three weeks after the robbery in a coordinated raid by Swedish and Norwegian police.
Another Swedish citizen was arrested in Oslo and charged with aiding and abetting the crime.
The seventh man, who is the twin brother of one of the defendants, is not being held in pre-trial custody.
The supposed ringleader has admitted to involvement in the crime but denies being one of the four involved in the raid.