  We study the N=1 supersymmetric solutions of D=11 supergravity obtained as a
warped product of four-dimensional anti-de-Sitter space with a
seven-dimensional Riemannian manifold M. Using the octonion bundle structure on
M we reformulate the Killing spinor equations in terms of sections of the
octonion bundle on M. The solutions then define a single complexified
G2-structure on M or equivalently two real G2-structures. We then study the
torsion of these G2-structures and the relationships between them.
