  We study neutrino emission from long gamma-ray bursts. The collapse of very
massive stars to black holes, and the consequent jet formation, are expected to
produce high-energy neutrinos through photomeson production. Such neutrinos can
escape from the source and travel up to the Earth. We focus on the case of
Population III progenitors for gamma-ray bursts. Neutrinos can be the only
source of information of the first stars formed in the universe. The expected
signal is rather weak, but we propose that gravitational lensing by nearby
supermassive black holes might enhance the neutrino emission in some cases. We
implement a Monte Carlo analysis to ponder the statistical significance of this
scenario. We suggest that an observational strategy based on gravitational
lensing could lead to the detection of neutrinos from the re-ionization era of
the universe with current instrumentation.
