A lawmaker who stood in for scandal-hit French presidential candidate Francois Fillon while the latter was prime minister has been placed under formal investigation by judges, a source close to the case told dpa on Friday.
The development came ten days after Fillon himself was placed under formal investigation by judges looking into allegations that his wife Penelope never worked for her taxpayer-funded salary as his parliamentary assistant.
Fillon, who says he is the innocent victim of a "political assassination," has sunk to third place in the polls since the claims about his wife's job were first published by satirical newspaper Le Canard Enchaine in January.
He now lies behind centrist Emmanuel Macron and far-right candidate Marine Le Pen, risking elimination in the first round of voting on April 23.
Marc Joulaud, who stood in for Fillon in the National Assembly from 2007 to 2012 while the latter was prime minister, was under investigation for possible embezzlement of public funds, the source close to the inquiry told dpa.
Joulaud continued to employ Penelope Fillon as a parliamentary assistant, and raised her average monthly salary from the 3,249 euros (3,500 dollars) she had earned working for her husband to 6,009 euros, according to data published by the Fillon campaign.
The development came as the controversy heated up with Fillon on Thursday night accusing Socialist President Francois Hollande of plotting to derail his campaign by leaking information about the investigation.
The charge, levelled during a fraught television appearance, drew an angry denial from the head of state, who said he had first learned of "the particularly serious affairs involving Mr Fillon" from the press.
The conservative candidate's appearance on France 2 television saw novelist Christine Angot ask him if he was engaging in "blackmail" by saying that he now understood what led another former French prime minister, caught up in a judicial investigation in the 1990s, to commit suicide.
Fillon also revealed that he had given back two made-for-measure suits, reportedly costing 6,500 euros each, that a businessman friend bought for him in February, and acknowledged that accepting them had been a mistake.
Hollande returned to the charge on Friday, telling France Bleu radio that he did not want to get involved in the presidential debate but "there is a level of dignity and responsibility that should be respected. I think Mr Fillon is falling short of that."
The authors of a forthcoming book, cited by Fillon to back up his claims, also went on air to deny that they had said Hollande maintained an apparatus for spying on his political rivals.
Co-author Olivia Recans told Radio Monte-Carlo that Fillon was "exploiting" their book and they had not been able to either prove or disprove that such an apparatus existed.
They did, however, conclude that information about ongoing investigations "found its way" to higher authorities, but that was a long-standing "bad habit," she added.
Frontrunner Macron also took aim Friday at Fillon and National Front leader Le Pen, who has defied summons from police and judges investigating claims she wrongfully claimed salaries for aides back from the European Parliament.
"There are two people who are caught up in affairs, and they are trying to get out of it by accusing everybody and casting suspicion on everybody," he said.
Socialist candidate Benoit Hamon also lashed out at Fillon, accusing him of having "a personal relationship with money that is rather incompatible with the ethics one expects of a head of state."
Polls favour Macron to win out against Le Pen in a likely May 7 run-off vote between the two.