  The unusual GRB 110709B triggered Swift/BAT twice, with a time difference of
$\sim 11$ minutes. Its light curve presented three noticeable peaks but only
two were originally identified. In this work, we describe each peak as due to a
different central-engine phase: the first one is the millisecond-protomagnetar
stage, the second one is the BH-formation collapse phase and the last one is
the Collapsar scenario with a Blandford-Znajek engine. Additionally, we analyze
and explain the afterglow phase evoking the standard fireball model. Our model
can successfully describe the timescales, fluxes and spectral indices observed
for GRB 110709B.
