By Bernardino Ndze Biyoa
Mann, 55, was flown last week to oil producer Equatorial Guinea, which has faced sharp international criticism for human rights abuses, after losing a legal appeal against extradition from Zimbabwe, where he had been in prison.
"He will receive a fair trial with all procedural and institutional guarantees," the government said. It gave no date for the trial.
Mann was arrested in March 2004 when he met a plane carrying dozens of men and military equipment which landed in Zimbabwe's capital Harare on what officials said was the first stop on their way to launching a coup against Obiang.
Zimbabwe's High Court last month dismissed Mann's argument that we would not receive a fair trial and would be tortured if he were deported to Equatorial Guinea.
FLAMBOYANT CAREER
He was jailed for four years by a Zimbabwean court in 2004 for buying weapons without a license -- which the prosecution said were intended for the Equatorial Guinea coup -- and was arrested again after his release for extradition.
Thatcher denied any involvement in the plan, and eventually agreed a plea bargain deal with South African authorities.
After assignments that reportedly included stints in Northern Ireland, Europe and Central America, Mann left the military in the 1980s for a new career in computer security.
Mann was also involved in the establishment of Sandline International, which news reports said was involved in a brutal civil war in Sierra Leone.