Police publish list of 'distinctive' stolen jewels to snare raiders
Police believe he was targeted because he was known to take jewellery home with him. Members of the public have reported seeing men staking out the street earlier that morning.
The value of the robbery has not yet been revealed but is understood to be a six-figure sum.
Detective Inspector Scott McMillan, who is leading the inquiry, said: "Mr Tankel is currently helping us with an inventory which we hope to be able to put out in the next few days.
"I expect them to be quite distinctive pieces so, hopefully, if one turns up in London or somewhere we will be notified."
Detectives are currently carrying out door to door enquiries and checking CCTV footage.
They are not ruling out the possibility the gang is from another part of the UK, but believe it had some local knowledge.
DI McMillan added yesterday: "I think there has been some planning involved."
The suspects made off in a dark-coloured vehicle, which was being driven by a fourth man. No words were spoken.
Mr Tankel, director of HW Tankel (Scotland) Ltd, suffered a minor eye injury in the attack.
It is the second time he has been targeted by thieves. In September 2001, raiders got away with gems worth 500,000 after using scaffolding to get inside the firm's Glasgow office.