Prosecutors in Guatemala say they have arrested ex-President Alvaro Colom and almost his entire former cabinet. Former Finance Minister Alberto Fuentes Knight, who is currently chairman of charity Oxfam International, was also nabbed. The arrests were part of a corruption probe involving a bus concession. Back in 2008, the government under Colom auctioned off 25-year concessions for Guatemala City bus routes and the private companies that won the contracts were later exempted from taxes. Prosecutors say the process was deeply flawed. Colom has denied any wrongdoing. The United Nations anti-corruption mission in Guatemala participated in the probe.