  We present a classically scale-invariant model with a confining dark sector,
which is coupled to the Standard Model through the Higgs portal. The galactic
centre gamma ray excess can be explained in this model by collision-induced
dark matter decays to b-quarks. We discuss the possibility to obtain the dark
matter relic density through thermal freeze-out, which however requires
excessive fine-tuning. We then instead focus on a freeze-in scenario and
perform detailed calculations and a parameter scan. We find that the observed
relic density and the gamma ray excess can be explained by a wide range of
parameters in this model.
