Decide if an edge cross some min-cut in flow network

Question

Let G=(V,E) be a flow network. Let e=(u,v) be an edge in E and let f be a maximum flow in G. Prove or Disprove:

Proof\disproof:

'If the residual graph Gf contains no directed path from u to v then e crosses some minimum cut in G.'

I haven't been able to find an example which condratics it nor to prove it