  We report on the unambiguous observation of the sub-cycle ionization bursts
in sequential strong-field double ionization of H$_2$ and their disentanglement
in molecular frame photoelectron angular distributions. This observation was
made possible by the use of few-cycle laser pulses with a known
carrier-envelope phase in combination with multi-particle coincidence momentum
imaging. The approach demonstrated here will allow sampling of the
intramolecular electron dynamics and the investigation of charge-state specific
Coulomb-distortions on emitted electrons in polyatomic molecules.
