In this work we present an experimental method which allows to investigate experimentally the energy and momentum distribution of the carriers which are injected by an STM tip into a metallic sample. We perform in situ ballistic-electron-emission microscopy (BEEM) and spectroscopy (BEES) simultaneously with atomic-resolution STM. The experiments are done at 77K on epitaxial CoSi2 films on Si(111) and Si(100). The potential of the method to improve on our understanding of tunneling on an atomic scale will be illustrated by two important findings: For the first time we have directly observed variations of the tunneling distribution on an atomic scale. The BEEM data also give evidence for a pronounced forward focussing of the angular distribution of the tunneling electrons.