The Nigerian authorities said on Tuesday that the eldest son of the late military dictator, General Sani Abacha, had been freed from detention after he signed documents pledging to return more than US $1 billion in state funds pilfered during his father's reign.
Mohammed Abacha was arrested in 1999 and held for more than three years over charges of murder and financial crimes.
A statement from President Olusegun Obasanjo's office said that, apart from undertaking to return state funds in his family's possession, Mohammed Abacha had agreed to be placed under around-the-clock surveillance and to leave his home town of Kano only with security clearance.
Abacha was acquitted by the Supreme Court two months ago of charges of conspiring to murder the wife of his father's political opponent in 1996. He was also granted bail by a court in Abuja on over 100 charges of money laundering and corruption.
Earlier in the year, Nigeria said a deal had been reached with the Abacha family for their return of over US $1 billion in state funds in return for Mohammed Abacha's freedom. The family was allowed to keep US $100 million, considered to have been acquired before the late general seized power in 1993.
However, government officials later said the Abacha family reneged on the deal.
Mohammed Abacha was released from prison custody last week but was immediately re-arrested by the police, sparking protests in Kano, northern Nigeria's biggest city.
Abacha's release on Monday came after a powerful delegation from Kano, including state governor Rabiu Kwankwaso and the city's traditional ruler, Ado Bayero, met President Obasanjo in the Nigerian capital, Abuja.
Following the meeting, the presidential statement said, Mohammed Abacha signed an undertaking to refund money to the state and abide by the terms of his release.
Obasanjo strongly denied suggestions that he was pursuing vengeance against the family of a man who had jailed him on false charges of plotting against him.
"I have no ill-feeling whatsoever, no malice whatsoever, no bad idea whatsoever against anybody and definitely not to the family of the late Sani Abacha," the president was quoted as saying.
"If only in the interest of the country, nobody should [be allowed to] perpetrate this kind of blatant corruption," Obasanjo added.
General Sani Abacha died in office - apparently of heart failure - in June 1998, which paved the way for democratic elections.
These were won by Obasanjo on his release from prison, ending a decade and half of unbroken, brutal military rule in Nigeria.