BORDEAUX (AFP) - French judges on Thursday grilled ex-president Nicolas Sarkozy about accusations his 2007 election campaign was financed with funds secured illegally from France’s richest woman.

In a case that could wreck the 57-year-old’s hopes of a political comeback, Sarkozy is suspected of taking financial advantage of elderly L’Oreal heiress Liliane Bettencourt when she was too frail to fully understand what she was doing.

Sarkozy’s appearance comes with his right-wing UMP party in turmoil after the battle to replace him degenerated into mud-slinging and both contenders claiming victory.

Examining magistrate Jean-Michel Gentil and two other judges were expected to spend most of the day quizzing Sarkozy about how he obtained funding from Bettencourt.

After flying into Bordeaux on a private plane, Sarkozy arrived for the hearing in a dark grey Renault minivan just before 9:15 am (0815 GMT), an AFP correspondent said.

A heavy police presence and many journalists surrounded the courthouse in Bordeaux.

Judicial sources have told AFP that Sarkozy could be formally indicted on a charge of taking advantage of someone in a position of weakness, although the magistrate also has the option of interrogating him as a witness under caution.

Bettencourt is now 90 and has been in poor health since 2006.

The allegation against Sarkozy is two-fold: that the money obtained from her took his campaign financing over legal limits and that it had been secured without her full knowledge or consent.

This latter claim was made by Bettencourt’s former accountant, Claire Thibout, in 2010. She told police that she had handed 150,000 euros in cash to Bettencourt’s right-hand man, Patrice de Maistre, on the understanding it was to be passed on to Sarkozy’s campaign treasurer, Eric Woerth.

Maistre withdrew a total of four million euros in cash from Bettencourt’s Swiss bank account in seven instalments between 2007 and 2009.

Investigators suspect some or all of the money could have found its way to Sarkozy or his party.

Claude Gueant, a close ally of Sarkozy who served as his interior minister, said the courts needed to show why his questioning was necessary.

“I would like to be absolutely convinced that this hearing is essential,” he told RTL radio, insisting there was no chance of illegal campaign financing because of “extremely rigorous” controls.

Sarkozy, who lost his immunity from prosecution after losing the presidential election to Socialist Francois Hollande in May, is facing a slew of legal inquiries.

As well as the Bettencourt case, Sarkozy is facing probes into contracts for opinion polls, an illegal police investigation into journalists and alleged kickbacks on a Pakistani arms deal used to finance the right in 1995, when Sarkozy was budget minister. Sarkozy has not ruled out another tilt at the presidency in 2017.

Efforts to find a replacement for him within his party have descended into chaos, with ex-prime minister Francois Fillon contesting the result of a bitter leadership election won by party secretary general Jean-Francois Cope.

Despite his legal troubles, a poll by firm CSA for BFM Television showed 52 percent of UMP supporters wanted Sarkozy to run in 2017, against only 24 percent for Fillon and 15 percent for Cope.

Sarkozy has denied any wrongdoing in the raft of probes, but the conviction last year of his predecessor Jacques Chirac has shown that French courts are willing to go after former leaders.