  The complete census of globular clusters formerly belonging to the Sgr dSph
and now deposited into the Galactic halo is an important contribution to our
comprehension of the evolution and disruption of this dwarf galaxy. We
investigate in this study the possibility that the poorly known "old" globular
AM 4 might be associated with the Sagittarius dwarf galaxy, and at the same
time provide more solid estimate of its basic parameters. New high quality BVI
photometry is presented, from which an improved Color Ma gnitude Diagram is
constructed, and estimates of age and distance are then derived. The distance
and Galactic position are finally investigated in details. AM~4 is found to be
a low luminosity (M$_V$=-1.82) cluster undergoing strong tidal stress by the
Milky Way and on the verge to be dissolved. Besides, and at odds with previous
suggestions, we provide evidences that AM 4 is indeed young, with an age around
9 Gyrs (as Terzan~7), but somewhat more metal poor ([Fe/H=-0.97]). AM~4 is
located at 33$_{-4}^{+3}$ kpc from the Sun, in a direction and at distance not
totally incompatible with the Sgr dSph stream. Although we significantly
improved our knowledge of AM 4, further studies are encouraged to obtain radial
velocity and metallicity to d emonstrate more firmly (or deny) the association
to Sgr
