Nigerian presidential election candidate and former boss of the county's anti-corruption agency -Nuhu Ribadu

Nuhu Ribadu, the former boss of Nigeria's anti-corruption agency, is known for his ruthless pursuit of corrupt individuals, winning him respect within his country and abroad.

The 50-year-old, the youngest candidate running for president, has more than 170,000 fans on Facebook and has previously been voted by the Nigerian press as "Man of the Year".

Ribadu graduated with a law degree and spent the first 18 years of his career working for the Nigerian police, where he became head of the legal and prosecution department in Abuja, the capital.

In 2003 he was selected by Olusegun Obasanjo, the former president, to run the country's highest anti-corruption office - the Economic and Financial Crimes Commission (EFCC).

During his term he gained a reputation as a corruption hunter, bringing more than 1,000 cases against politicians and businessmen.

He won international praise for arrests of graft suspects and seizures of assets and received the World Bank's 2008 Jit Gill Memorial Award for Outstanding Public Service.

But he was also criticised of being a political pawn, only chasing enemies of Obasanjo.

When Umaru Musa Yar'Adua was sworn in as president in 2007, Ribadu was dismissed from his position and accused of failing to declare his own assets.

Two years later he fled Nigeria for Britain and the United States after a reported attempt on his life, which he has said was a result of making dangerous enemies during his time at the EFCC.

He returned in 2010 when charges against him were dropped following the death of Yar'Adua, and since opened a bid to lead the Action of Congress Nigeria (ACN) party.

Ribadu has pledged to reduce government spending, tackle poverty, develop the Niger Delta region and fight corruption. But few believe he will make any headway due to his lack of experience in politics.