A 31-year-old Ottawa man has been charged with arson in one of two suspicious fires to burn through a four-storey commercial building at the corner of Bank and Somerset streets in a period of 16 days.

Ottawa police arrested and charged Robert Gill on Wednesday in connection with a fire at 275 Bank Street on Sept. 15. He faces both arson and break-and-enter charges.

Meanwhile, the Ontario fire marshal's office has concluded an early morning fire that broke out in the same building on Wednesday was also the result of arson.

Investigators say there is no evidence yet to support the theory the building was targeted because of its tenants, which included the Bangladesh high commission and a U.S. military procurement agency.

Police say they expect to lay further charges.

With files from The Canadian Press