Blazars are active galactic nuclei which have their relativistic particle jet pointing towards Earth
and have been observed to emit gamma rays to very high energies. They are also candidates
for the yet-unknown accelerators of ultra-high-energy cosmic rays. In such a scenario, their
gamma-ray emission might be associated with neutrinos produced by hadronic interactions in
the jet. Correlating the astrophysical neutrinos detected by IceCube, a cubic-kilometre neutrino
telescope at the South Pole, with the gamma-ray emission from blazars could therefore reveal
the origin of cosmic rays. In our method we focus on periods where blazars show an enhanced
gamma-ray flux, as measured by Fermi, thereby reducing the background of the search. At the
same time we test for the combined emission of a whole blazar population in a stacked search.
A detection of such a neutrino flux could lead to the discovery of a source class responsible
for cosmic-ray acceleration. We present sensitivities and discovery potentials for a selection of
Fermi monitored sources and one year of IceCube data.