A court in Nigeria has sentenced to death a key aide of former military dictator Sani Abacha for the murder of another politician’s wife

Army major Hamza al-Mustapha, who has been in detention since 1999, is alleged to have killed the wife of former presidential candidate Moshood Abiola in 1996.

Another former aide to Abacha was also sentenced to death on the same charges.

Judge Mojisola Dada of the Lagos high court ruled that Mustapha was guilty of conspiracy and murder in connection with the death of Kudiratu Abiola.

Evidence was manifestedly heavy that they killed Kudiratu Abiola. In view of this, they are guilty of conspiracy and murder, Dada said in her ruling.

The prosecution has proved its case beyond all reasonable doubt. In view of this, they should be hanged.

Mustapha had served as Abacha’s chief of security and has always maintained his innocence. Mustapha's defense lawyer Olalekan Ojo said he would appeal the court judgment.

Abiola, a wealthy businessman. was reportedly the victor of the election in 1993, but the results were nullified by the army which staged a coup. After Abiola declared himself the winner, he was charged with treason and imprisoned.

The chain of events prompted unprecedented protests in the streets of Nigeria.

Abacha, who ruled Nigeria from 1993 to 1998, has been accused of embezzling billions of dollars during his reign. He was also believed to have committed gross human rights abuses. He was also believed to have hunted down and murders scores of opponents both in Nigeria and abroad.

After Abacha died in 1998, Abiola was due to be released, but he too died shortly thereafter in his prison cell while meeting with American diplomats. International pathologists determined he died of natural causes, although Abiola's supporters have maintained the military killed him.

The Nobel literature laureate Wole Soyinka, a vociferous critic of Abacha, was among those who fled into exile.