  The large number of quasars found in the Sloan Digital Sky Survey has allowed
searches for elusive, clear lines of sight towards HeII Ly-alpha absorption, a
sensitive probe of the intergalactic medium. The few known systems indicate
that HeII reionization occurs at z>3. We report the detection of a HeII
Ly-alpha absorption edge in a quasar spectrum at z=3.50, the most distant such
feature found to date. The candidate quasar was selected from a z~3 sample in
the SDSS spectroscopic quasar survey and confirmed as part of an HST/STIS SNAP
survey. We discuss the general characteristics of the absorption feature, as
well as the probability for discovery of additional such objects.
