  We present an alternative method to X-ray surveys for hunting down the
high-redshift type-2 quasar population, using Spitzer and VLA data on the
Spitzer First Look Survey. By demanding objects to be bright at 24 microns but
faint at 3.6 microns, and combining this with a radio criterion, we find 21
type-2 radio-quiet quasar candidates at the epoch at which the quasar activity
peaked. Optical spectroscopy with the WHT confirmed 10 of these objects to be
type-2s with 1.4 < z < 4.2 while the rest are blank. There is no evidence for
contamination in our sample, and we postulate that our 11 blank-spectrum
candidates are obscured by kpc-scale dust as opposed to dust from a torus
around the accretion disk. By carefully modelling our selection criteria, we
conclude that, at high redshift, 50-80 % of the supermassive black hole growth
is obscured by dust.
