On a four-dimensional hyperbolic manifold with finite volume

In article [1] the authors construct and classify all the hyperbolic space-forms $H^n/\Gamma$ where $\Gamma$ is a torsion-free subgroup of minimal index in the congruence two subgroup $\Gamma_2^n$ for $n=3,4$. In the present paper some hyperbolic $3$- and $4$-manifolds are constructed that are absent in [1].