The armed raiders who stole more than #1m from an Aberdeen security depot might have made their getaway in vehicles which appeared to belong to the police, writes Graeme Smith.

Minutes after the robbery two of the vehicles involved in Thursday's raid on the Securitas depot on the Altens industrial estate, a white Vauxhall Senator and a white Bedford Midi Van, overtook a queue of cars and witnesses reported seeing blue flashing lights in their windscreens.

The Senator, identical to the vehicles formerly used by Grampian Police, and the van, were stolen in Aberdeen almost two weeks before the raid.

Detective chief inspector Peter Simpson said the raiders managed to throw #1m into the van within four minutes and make their getaway. A further substantial amount of money was in the Securitas building at the time. Grampian Police said it was not clear if the raiders had left that because they had set themselves a time limit.

Witnesses have told police how the Senator and the van made their way to Cove down Hareness Road. They pulled over to the wrong side of the road to pass a string of eight or nine cars waiting to turn right and witnesses reported seeing blue flashing lights in both vehicles, although there were no sirens.

The vehicles left Securitas at 5.07pm and passed the traffic queue two or three minutes later. They were next sighted in Portlethen, where they were later found, at 5.28pm. The Senator dropped off one person in the Asda car park where it is believed he collected another car.

An hour and a half later the Senator and the van were spotted ablaze behind an embankment at the rear of a church car park in Portlethen.

Mr Simpson said they were seeking confirmation from the public about the route the vehicles took from Cove to Portlethen. He also wanted to know where the vehicles had been before they were set alight.

He said: ''There must have been a change over at some point where the money which was in the van was taken out and transferred to some other vehicle or left in some other place.''

Police had received a good response from the public, he said, but they still did not know where the two vehicles had been for almost a fortnight from the time they were stolen in Aberdeen until they were used in the robbery.