Detectives believe a gang which carried out a £20,000 jewellery robbery in Kent was also responsible for a failed attempt to raid a security van.
The raiders grabbed the jewellery after using a sledgehammer to smash the window of Canterbury Jewellers and Pawnbrokers on Tuesday.
They got away from St Peter's Street in a Seat Leon found abandoned in Cherry Garden Road on Wednesday morning.
The same car was used in the attempted robbery at Morrison's on 2 February.
The vehicle pulled up as cash was being delivered by security van. The security staff member shut himself in the store and no money was taken.
The car, which has copied registration plates, was stolen from Hertfordshire.
"The jewellery robbery and last week's attempt appear to be down to the same group," said Det Insp Nick Greenan.
"Witnesses to yesterday's robbery have provided descriptions and we are going through these at the moment.
"We would appeal to anyone who may have seen the vehicle in the last week to contact us.
"Was it left parked in your street? Did you see any suspicious activity around a garage or lock-up?"