A storage unit behind WH Smith between 01.30-02.00hrs on Tuesday (8th January) 2013.
Tuesday's blaze follows an arson attack on Poundland in Central Road on 11th December last year.
Det Con Matt Harris, of Sutton CID, said he wants to hear from anybody who may have seen someone running away from the scene in the area around Stone Place car park (by Waitrose).
“Setting light to any building is a very serious crime and could go on to cause serious injury or loss of life. We are asking for the public’s help to catch the person responsible,” he said.
If you have any information that could help police, please contact Det Con Harris on 020 8649 0747.
Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.