The formation of the Galactic halo is currently best explained by the combination of two scenarios which previously were regarded as competing models. Based on the kinematics of metal-poor halo field stars, Eggen, Lynden-Bell & Sandage (ELS, 1962) proposed that the halo formed during a rapid, smooth collapse from a homogeneous primordial medium. Searle & Zinn (SZ, 1978) argued a halo formation via the gradual merging of many sub-galactic fragments. The SZ scenario has been strengthened by the observational evidence accumulated during the past decade. The discovery of the Sagittarius dwarf galaxy (Ibata, Gilmore & Irwin 1994), in a process of dissolving into the Galactic halo, argued in favour that accretion events can take place in the Milky Way. The possibility that accretion events may leave observable fossil records in the halo is also supported by theoretical models of tidally disrupted dSph satellites (Johnston, Spergel & Hernquist 1995; Oh, Lin & Aarseth 1995; Piatek & Pryor 1995). We present our preliminary results of a long-term project to investigate the process of accretion and tidal disruption of dSph satellites in the Galactic halo and, in particular, to search for new tidal tails in a sample of nearby dSph satellites of the Milky Way. The presence of a possible tidal debris in Ursa Minor and Sculptor dSphs and the results of our survey for a tidal extension along the NW semimajor axis of Saggitarius is discussed.