Minimizability of developable Riemannian foliations

Let (M, F) be a closed manifold with a Riemannian foliation. We show that the secondary characteristic classes of the Molino's commuting sheaf of (M, F) vanish if (M, F) is developable and pi(1)M is of polynomial growth. By theorems of Alvarez Lopez in (Alvarez Lopez, Ann. Global Anal. Geom., 10: 179-194, 1992) and (Alvarez Lopez, Ann. Pol. Math., 64: 253-265, 1996), our result implies that (M, F) is minimizable under the same conditions. As a corollary, we show that (M, F) is minimizable if F is of codimension 2 and pi(1M) is of polynomial growth.