  We show that the unrestricted wreath product of a sofic group by an amenable
group is sofic. We use this result to present an alternative proof of the known
fact that any group extension with sofic kernel and amenable quotient is again
a sofic group. Our approach exploits the famous Kaloujnine-Krasner theorem and
extends, with an additional argument, to hyperlinear-by-amenable groups.
