  We consider group-subgroup pairs in which the group is a semidirect product
and the subgroup is contained in the normal part. We give conditions for the
pair to be a Hecke pair and we show that the enveloping Hecke algebra and Hecke
C*-algebra are canonically isomorphic to semigroup crossed products,
generalizing earlier results of Arledge, Laca and Raeburn and of Brenken.
