Some hyperbolic manifolds

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].