  We propose that the vacuum state of a scalar field around a black hole is a
modified Unruh vacuum. In (1+1) dimensions, we show that a free-faller close to
such an horizon can be modelled as an inertial observer in a modified Minkowski
vacuum. The modification allows for information-leaking correlations at high
frequencies. Using a Gaussian detector centred at $k_0$, we find that the
expectation value of the number operator for a detector crossing the horizon is
proportional to $1/|k_0|$, implying that the free-faller will observe unbounded
numbers of high energy photons, i.e. a firewall.
