Shopping centre The Mall in Blackburn 'set on fire by burglars'
Burglars who broke into a shopping centre to steal from a jewellers also set an entrance on fire, causing "significant damage", police have said.
Lancashire Police said up to eight men wearing balaclavas smashed into Chris Shan Jewellers in Blackburn's The Mall overnight using hammers and crowbars.
They then set the Church Street entrance on fire at about 02:30 GMT.
A force spokesman said the men fled through an exit near County Hall with "an unknown quantity of jewellery".
Police are also exploring whether a second fire reported soon after the burglary, involving two burning cars at the Citroen garage on Throstle Street, could be linked.
Det Insp Tim McDermott said CCTV footage of the "well-planned" theft indicated "other offenders" may also have been involved.
Three areas of the shopping centre have been closed to allow Lancashire Police and the fire service to carry out investigations.