The son of the deposed Libyan leader Muammar Gaddafi has welcomed the detention of Nicolas Sarkozy and repeated his offer to provide evidence that the former French president’s 2007 election campaign was funded illicitly by the Libyan government.

Saif al-Islam – who made the allegations in an exclusive interview with Euronews in 2011 – told our sister channel Africanews that he regretted it had taken the French authorities seven years to act.

In a series of messages sent by WhatsApp, Gaddafi’s son claimed he had witnessed the first portion of money being delivered in Tripoli to Sarkozy’s former chief-of-staff Claude Guéant.

He added that he was one of several witnesses who were ready to testify – including Abdallah Snoussi, ex-director of the Libyan intelligence services, and Bashir Salah, former chief executive of Libya Investment.

Snoussi has a recording of the first meeting between Sarkozy and Gaddafi in Tripoli before his 2007 election campaign, al-Islam claims. He alleges that both men made a second delivery of cash to Paris.

Nicolas Sarkozy – who was President of France from 2007 until 2012 – has been questioned for a second day by police near Paris. Investigations were prompted by the French news website Mediapart’s publication of accusations made by a Franco-Lebanese businessman, Ziad Takieddine, who said he transferred €5 million to Guéant from Gaddafi’s former intelligence chief.

There has been no comment from Sarkozy or his lawyers since the 63-year-old was taken into custody on Tuesday. In the past the ex-president has dismissed the accusations as “grotesque” and a “manipulation”. His party, Les Républicains, have said they fully support their former leader.

Takieddine has been quoted by a Lebanese newspaper as saying he acted as an intermediary between France and Libya when Sarkozy was interior minister, before his presidential bid. Five months after his election, Gaddafi came to Paris on his first state visit to a Western country in decades.

However, by 2011 the then French president had turned against the Libyan leader. France was at the forefront of NATO-led airstrikes against Gaddafi’s forces that helped rebel fighters overthrow the dictator and his regime.

It was around this time that Gaddafi’s son, Saif al-Islam, made his comments to Euronews as he expressed outrage at France’s recognition of the rebel groups’ interim government set up in Benghazi.