Forensic experts are examining a white Transit van found in Kent with a quantity of money thought to be from the multi-million pound Securitas raid.
Police say it is too early to say how much cash was recovered
It is hoped the vehicle, found in Ashford, will yield more clues in the hunt for the gang who stole up to £50m from a depot in Tonbridge on Wednesday.
The forensic analysis means it could be days before it is known how much cash was recovered, police have said.
Three people arrested over the robbery have been released on police bail.
A 29-year-old man and a 31-year-old woman were detained at separate addresses in Forest Hill, south London, on Thursday.
The armed gang forced the manager to let them into the depot
Another 41-year-old woman was held in Bromley, south-east London. They have all been bailed pending further inquiries.
An armed gang raided the Securitas premises in Vale Road, Tonbridge, during the early hours of Wednesday.
Earlier they had kidnapped the depot manager, 51-year-old Colin Dixon, and his wife and young son.
The Transit van was found on Friday after a tip-off from a member of the public.
Forensic officers wearing white overalls, gloves and face masks removed black bundles from the van, found at the Ashford International Hotel.
A Kent police statement said money had been recovered from the vehicle, but it was "too early to speculate on how much".
"We are linking this to Wednesday's robbery at the Securitas depot in Tonbridge, but we cannot say yet how significant the find is," it added.
These e-fits show one of the robbers with and without a beard
The van and its contents were removed from the hotel for the forensic examination.
Assistant Chief Constable Adrian Leppard said: "I am very grateful to the member of the public who made the call to us.
"I am as keen as you to know exactly how much cash [was in the van] but we just do not know at this stage."
The Bank of England said a £25m payment it received from Securitas on Wednesday had covered all its losses.
The rest of the stolen notes did not belong to the bank.
An audit of its own notes held at Tonbridge has now been completed but an audit of the rest of the cash is still under way.
Kent Police have now recovered several vehicles during the course of their investigations.
Mr Dixon's silver Nissan Almera was discovered at the Cock Horse pub in Detling.
A Volvo saloon, believed to have been used in Mr Dixon's abduction by robbers posing as police officers, was found burning in Burberry Lane in the village of Leeds, near Maidstone.
A red van with Parcelforce markings, thought to have been involved in the robbery, was recovered from the Hook and Hatchet pub in Hucking.
Police said they had found another vehicle in Burberry Lane, although no more details about it have yet been revealed.
The white Renault lorry used by the gang is still missing.
Meanwhile, Kent Police have also released a description and computer image of one of the men who kidnapped Mr Dixon.
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.