Former French President Nicolas Sarkozy was taken into police custody on Tuesday morning over allegations that he received campaign funding in 2007 from Libya’s former dictator Muammar Gaddafi.

A former minister and close ally of Sarkozy, Brice Hortefeux, is also being questioned in connection to the allegations that Libya helped finance Sarkozy’s successful campaign more than a decade ago, another source close to the probe said.

Investigators are examining claims that Gaddafi’s regime secretly funneled €50 million into the coffers of Sarkozy campaign – more than double the legal limit in France and a gross violation of the country’s strict rules on foreign financing.

Sarkozy, who served one-term as president from 2007 to 2012, has always denied that he received any illicit campaign funding and dismissed the Libyan allegations as “grotesque”.

In January, a French businessman suspected by investigators of transferring money from Gaddafi to Sarkozy’s campaign was arrested in the United Kingdom but released on bail after he appeared in a London court.

Sarkozy has already been ordered to stand trial in a separate matter concerning the financing of his failed re-election campaign in 2012, when he was defeated by former President Francois Hollande.