  We report the observation of a very exotic decay mode at the proton
drip-line, the $\beta$-delayed $\gamma$-proton decay, clearly seen in the
$\beta$ decay of the $T_z$ = -2 nucleus $^{56}$Zn. Three $\gamma$-proton
sequences have been observed after the $\beta$ decay. Here this decay mode,
already observed in the $sd$-shell, is seen for the first time in the
$fp$-shell. Both $\gamma$ and proton decays have been taken into account in the
estimation of the Fermi (F) and Gamow Teller (GT) strengths. Evidence for
fragmentation of the Fermi strength due to strong isospin mixing is found.
