Watches worth £389,000 were stolen from a jewellery shop at the intu Potteries shopping centre, according to Staffordshire Police.
A gang dressed in dark clothing, some with face coverings, broke into the centre through the front doors just after 2.35am on Thursday, March 10.
Some of them started a started a fire at the main entrance to the centre and raided Beaverbrooks, taking the haul of top-name watches, including Breitling.
Staffordshire Police Detective Chief Inspector Ricky Fields, who is leading the investigation, said: “This was very much a pre-planned crime and the offenders were very methodical.
“They were in and out of the centre within minutes and have stolen a number of high value watches.”
Detectives are carrying out detailed inquiries, focussing on trawling through CCTV and Automatic Number Plate Recognition (ANPR) cameras from around the city to identify suspicious vehicles.
DCI Fields added: “I’m also keen to hear from anyone who saw suspicious persons and/or activity in and around Beaverbrooks and the shopping centre in the days leading up to the break-in.
“Any information people have, however small or insignificant they think it is, could prove a vital piece of the jigsaw.
“I’d also ask people to be on their guard if they are offered such high value watches at a knockdown price, or come across them in suspicious circumstances.”
Anyone with information should contact Staffordshire Police on 101 quoting incident number 36 of March 10 or Crimestoppers, anonymously, on 0800 555 111.