Your aprocach in this is the problem. Your girlfriend's bother in law's customers and staff, on the way to that establishment, and within, could easily be spreading the virus. Untested, without symptoms, simply going about their usual lives. This is why we're seeing tested cases in the US (now that there's tests) rise so suddenly. There is no 'only 1 person has it in a town). That was my town yesterday, with only one case, and then bam, more people got tested.