  Numerical calculations are shown to reproduce the main results of recent
experiments involving nonlocal spin control in nanostructures (N. J. Craig et
al., Science 304, 565 (2004)). In particular, the splitting of the
zero-bias-peak discovered experimentally is clearly observed in our studies. To
understand these results, a simple "circuit model" is introduced and shown to
provide a good qualitative description of the experiments. The main idea is
that the splitting originates in a Fano anti-resonance, which is caused by
having one quantum dot side-connected in relation to the current's path. This
scenario provides an explanation of Craig et al.'s results that is alternative
to the RKKY proposal, which is here also addressed.
