  Let $P$ be a Camina $p$-group that acts on a group $Q$ in such a way that
$C_P (x) \subseteq P'$ for all nonidentity elements $x \in Q$. We show that $P$
must be isomorphic to the quaternion group $Q_8$. If $P$ has class $2$, this is
a known result, and this paper corrects a previously published erroneous proof
of the general case.
