In 1982, Zaks, Perles and Wills discovered a d-dimensional lattice simplex S d,k with k interior lattice points, whose volume is linear in k and doubly exponential in the dimension d. It is conjectured that, for all d ≥ 3 and k ≥ 1, the simplex S d,k is a volume maximizer in the family P d (k) of all d-dimensional lattice polytopes with k interior lattice points. To obtain a partial confirmation of this conjecture, one can try to verify it for a subfamily of P d (k) that naturally contains S d,k as one of the members. Currently, one does not even know whether S d,k is optimal within the family S d (k) of all d-dimensional lattice simplices with k interior lattice points. In view of this, it makes sense to look at even narrower families, for example, some subfamilies of S d (k). The simplex S d,k of Zaks, Perles and Wills has a facet with only one lattice point in the relative interior. We show that S d,k is a volume maximizer in the family of simplices S ∈ S d (k) that have a facet with one lattice point in its relative interior. We also show that, in the above family, the volume maximizer is unique up to unimodular transformations.