Police compiled e-fits of the kidnapper with and without a beard
Police have released a description and computer image of one of the armed robbers involved in the multi-million pound Securitas depot raid in Kent.
The man posed as a police officer to trick depot manager Colin Dixon into getting into a car with him on Tuesday.
He wore a police-style cap and a high visibility jacket.
He is described as white, 6ft to 6ft 1in tall, with a scruffy, "wiry and wispy" ginger beard, which could have been false.
The man's hair was thought to be a different colour from the beard.
He had dark eyebrows and freckles on his cheeks.
The computer image of the man was produced by police with the help of Mr Dixon.
The depot manager, 51, was kidnapped by robbers pretending to be police officers, at the same time as his wife and son were abducted from their home in Herne Bay.
The young boy should have been celebrating his ninth birthday on Friday, but instead police said the whole family had been left traumatised by their experience.
"We've tried to make it special for him," said Assistant Chief Constable Adrian Leppard.
"He's had presents today - we're trying to get some of our own presents to him.
"We're trying to give them all the support we can.
"Some of the members of the family are having trouble sleeping, but they are recovering day by day."
Three people are being questioned in connection with the robbery at police stations in Kent.
Mr Dixon's Almera was recovered at the Cock Horse pub in Detling
A 41-year-old woman was arrested at the Portman Building Society, in Bromley, south-east London, on suspicion of handling stolen goods.
Kent Police said she tried to bank "an amount of cash that had wrapping indicating it had come from the Securitas depot at Tonbridge".
"Detectives are trying to determine whether this is connected to the investigation," a statement said.
ACC Leppard added: "This woman could be completely innocent - we really don't know at the moment - but it [her arrest] was an obvious course of action to take by the building society and the Metropolitan Police at the time."
A man, 29, and a woman, 31, were arrested in south London on Thursday on suspicion of conspiracy to commit robbery.
Forensic tests are taking place on four vehicles thought to have been involved.
A tip-off from a member of the public led to the recovery of a white Ford Transit van in the car park of Ashford International Hotel on Friday.
Police believe this burnt-out Volvo was used by the robbers
Mr Dixon's Nissan Almera and a Volvo believed to have been used to kidnap him were found on Thursday, as well as a red van, thought to be a former Parcelforce vehicle.
ACC Leppard said: "The recovery of these cars and the van is an important development for us.
"We now think that a dark saloon car used by the gang to transport the depot manager's wife and their young son may have linked up with the red van with Parcelforce markings in the Faversham area at some time on Tuesday evening, at which point the woman and boy were transferred to the van."
The dark Volvo saloon was found burning in Burberry Lane in the village of Leeds, near Maidstone, late on Thursday night.
"We can't confirm that this is definitely linked with the case but it is a good lead for us at the moment," said ACC Leppard.
He also said another vehicle was recovered from Burberry Lane, but he could not yet give any more details.
The white 7.7 tonne Renault lorry used to transport the cash is still missing.
The amount of money stolen could be up to £50m, although police are still unable to confirm the exact figure.
A £2m reward has been offered for information about the raid.