The gang behind a raid on two upmarket London jewellery stores stole valuables with an estimated retail value of £380,000, police have said.
The thieves snatched the haul from the De Beers and Omega stores in the Royal Exchange shopping arcade in the City of London at about 2200 BST on Saturday.
The City of London Police said they believed four thieves broke through a padlocked gate then smashed the shop windows with sledgehammer.
No arrests have been made.
The thieves, wearing hooded tops and balaclava, took diamond jewellery and watches from the window displays, the City of London Police said.
No other stores were targeted and the gang left in the same red BMW they arrived in, police added.
De Beers is best known for its diamond jewellery and Omega for luxury Swiss watches.
Detectives are examining CCTV images from the arcade and surrounding streets, as well as number plate recognition cameras, in a bid to identify the car.
Police officers worked through the night at the store to gather forensic evidence and catalogue what was stolen and how much it was worth.
Det Ch Insp Steven Chandler said: "We need the assistance of the public in tracing the car used in the offence, the criminals involved and the items stolen."
Former Flying Squad officer John O'Connor suggested the raiders may have had inside assistance.
He told BBC Radio 4's Today programme: "The villains did not drive up on the off-chance they could get through security gates.
"There is always the suspicion that they had somebody on the inside."
The Royal Exchange, built in 1565, is located between Threadneedle Street and Cornhill and boasts more than 30 luxury stores.