When the Empire realized that the jettisoned escape pod had droids in it they started a complete search of the entire planet this included all settlements large and small.
When the news reached Mos Eisley the Imperial Garrison started there search all over the city especially the slum areas as they knew this would be a great place to start as all types of dealings happened in this part of town especially smuggling and slave trades.
The only problem going into this part of town is that there is no law at all, so all Imperial Troops have to be extra careful when entering this treacherous area.
Sandtroopers - The troopers are from hasbro and have had the joints superglued and then puttied up.
The Base - the base is from a two dollar shop, the walls of the derelict buiding are pieces of foam glued together and then a mix of plaster and woodglue was applied over the top of it.
The pipes and bits and pieces on the walls are old pieces of straw and parts from the pits box, the droid parts are from Hasbro and are from the parts bin and the posters I got permission to use from bama287 over at www fanpop com and as always onece complete the whole dio was painted and weathered using Vallejo, GW paints and pastels.