B. Y. Chen and T. Teng
affirmed that almost umbilic isometric immersions of an n-dimensional manifold
in Rn+2 have zero normal curvature (R⊥= 0). In this paper we exhibit
a counterexample to this statement and we prove that either R⊥= 0 or
there exists (locally) an isometric immersion of this manifold in Rn+2 with
R⊥= 0. These immersions are conformally flat and we study their local
geometry.