  The square lattice spin-1/2 antiferromagnet containing a dilute
concentration, $\delta$, of randomly placed ferromagnetic nearest-neighbor
bonds is studied at low-temperature via non-linear $\sigma$-model techniques
and by exact diagonalization. We generally find that long-range N\' eel order
is destroyed above a critical strength in the defective ferromagnetic exchange
coupling-constant given by $|K_c|/J\sim \delta^{-1/2}$. We also observe large
statistical fluctuations both in the spin-stiffness and in the
antiferromagnetic structure-factor near this critical point, suggesting the
onset of a spin-glass phase.
