Let $G$ be a finite solvable group. Suppose that $H$ is a minimal normal subgroup of $G$. Then we can raise $H$ to a composition series since $G$ is finite. Since $G$ is solvable, every composition factor in the composition series is of prime order. Since $H$ is of prime order, simple and nontrivial we can say that it is isomorphic to $\mathbb{Z}/p\mathbb{Z}$.
Is there any flaw in this proof?