  We present a detailed study of the electronic and magnetic ground state
properties of Fe$_{1-x}$Co$_{x}$Si using a combination of macroscopic and
microscopic experimental techniques. From these experiments we quantitatively
characterize the metal-insulator transition and magnetic/non-magnetic quantum
phase transition occurring at low doping levels in Fe$_{1-x}$Co$_{x}$Si. From
our study, we find a surprising closeness of the critical composition of the
metal-insulator transition at $x_{\mathrm{MIT}} = 0.014$ and the quantum phase
transition at $x_{\mathrm{LRO}} \sim 0.024-0.031$. It suggests that these
effects are cooperative and depend on each other.
