(Ecofin Agency) - Former Nigerian Petroleum Minister Diezani Alison-Madueke has been arrested in the U.K. on suspicion of bribery and money laundering offenses, according to an official in the Nigerian presidency circle and another with links to her family said.

Alison-Madueke a former president of the Organization of Petroleum Exporting Countries who served as oil minister for five years until her party lost elections in March was arrested in London on Friday 2nd of October 2015.

It was alleged that several oil-related scandals involving billions of dollars, ranging from fuel subsidy fraud to missing crude revenues were unaccounted for under her watch.

Nigeria is cooperating with U.K. authorities, a police spokesman in London said

 “The government is aware of the arrest and is cooperating with the investigators in the U.K.,” Garba Shehu, a spokesman for President Muhammadu Buhari, told Bloomberg.

 The National Crime Agency, in a short statement on its website said its International Corruption Unit had arrested five people across London on suspicion of bribery and corruption offences on Friday, without naming the suspects.

Meanwhile, Investigators with the Economic and Financial Crimes Commission (EFCC) are presently interrogating a former managing director of one of the subsidiaries of the Nigerian National Petroleum Corporation (NNPC) and three former executive directors of the oil corporation under Alison-Madueke.

They are said to be under investigation by officials of the Subsidy Unit of the EFCC and their counterparts from the National Crime Agency of the United Kingdom in relation to the former minister’s case.

An EFCC source said the ex-minister might appear in court today adding that the EFCC investigation into the activities of the NNPC was not just about Alison-Madueke. The source said that more people could be grilled in relation to the probe of the corporation.

However to the source the UK Police, which had been monitoring the former minister for close to two years, had substantial evidence before moving against her.