President Paul Biya’s anti-corruption drive suffered yet another embarrassing twist after an ex-minister died in jail on Thursday – after more than four years without trial.

Henri Engoulou, former minister delegate of economy and finance in charge of the budget died at the Yaounde central hospital after falling sick at the Kondengui prison.

Communication minister Issa Tchiroma confirmed the death but did not specify what killed the former minister.

Engoulou was arrested in an over one billion embezzlement matter also involving the former finance minister Polycarpe Abah Abah.

His trial suffered long unspecified delays and was still at the stage of finalizing the shortlist of witnesses during his most recent court appearance in January.

Engoulou denied accusations of theft of public funds, which disappeared from a BISEC bank account.

His arrest was part of a sweeping campaign launched by Biya in 2006 to root out high-level corruption from the public service.

But the operation called sparrow-hawk has suffered serious credibility problems due to long legal procedures and criticisms that arrests are politically motivated.

Before becoming minister of budgets, Engoulou worked in numerous top positions at the ministries of economy and finance, public health and public service.

His death come shortly after that of the former secretary-general of secondary education Catherine Abena, arrested in 2010 but released in a very bad shape after many months of hunger strike.