  We report on a numerical reinvestigation of the Aoki phase in lattice QCD
with two flavors of Wilson fermions where the parity-flavor symmetry is
spontaneously broken. For this purpose an explicitly symmetry-breaking source
term $h\bar{\psi} i \gamma_{5} \tau^{3}\psi$ was added to the fermion action.
The order parameter $<\bar{\psi} i \gamma_{5}\tau^{3}\psi>$ was computed with
the Hybrid Monte Carlo algorithm at several values of $(\beta,\kappa,h)$ on
lattices of sizes $4^4$ to $12^4$ and extrapolated to $h=0$. The existence of a
parity-flavor breaking phase can be confirmed at $\beta=4.0$ and 4.3, while we
do not find parity-flavor breaking at $\beta=4.6$ and 5.0.
