  Corruption crimes demand highly coordinated actions among criminal agents to
succeed. But research dedicated to corruption networks is still in its infancy
and indeed little is known about the properties of these networks. Here we
present a comprehensive investigation of corruption networks related to
political scandals in Spain and Brazil over nearly three decades. We show that
corruption networks of both countries share universal structural and dynamical
properties, including similar degree distributions, clustering and
assortativity coefficients, modular structure, and a growth process that is
marked by the coalescence of network components due to a few recidivist
criminals. We propose a simple model that not only reproduces these empirical
properties but reveals also that corruption networks operate near a critical
recidivism rate below which the network is entirely fragmented and above which
it is overly connected. Our research thus indicates that actions focused on
decreasing corruption recidivism may substantially mitigate this type of
organized crime.
