In this paper a fivefold twinning silver nanowire is mechanically tested in real time within a transmission electron microscope using an atomic force microscopy sensor. Our experimental setup allows us to measure, by bending the silver nanowire, the elastic modulus (E), the fracture toughness (KIC) and the stress intensity factor (σI) for elastic and plastic deformation regions and finally the fracture of the nanowire. Data of the force applied and the bending of the nanowire was recorded during the deformation and after the point of fracture. The mechanical properties of the nanowire were extracted and compared with nanoindentation using atomic force microscopy.