International athletics has been plunged into a major corruption crisis after French police confirmed former IAAF president Lamine Diack is being investigated over an alleged payment of more than €200,000 to cover up doping offences by Russian athletes.
A prosecutor from the Parquet National Financier (PNF) - the office that handles financial prosecutions in France - confirmed that Diack is being investigated.
Diack and his adviser Habib Cisse have been formally interviewed, sources with knowledge of the investigation have confirmed. The IAAF's anti-doping director Gabriel Dolle has been taken into custody.
The prosecutor said the investigations included a probe into allegations that Diack was paid more than €200,000 to cover up positive drugs tests.
Officers visited the headquarters of international athletics in Monaco on Tuesday and took documents, a statement from the IAAF confirmed.
It is understood IAAF president Lord Coe, who took over from Diack in August, was at the offices at the time and volunteered to speak to the investigators.
An IAAF statement said: "The IAAF confirms that, emanating from separate ongoing investigations by WADA's independent commission and the IAAF's own independent Ethics Commission into allegations surrounding its anti-doping rules and regulations, a French police investigation has now commenced.
"The IAAF is fully cooperating with all investigations as it has been from the beginning of the process.
"As part of the French investigation, police visited the IAAF HQ offices yesterday to carry out interviews and to access documentation."
The scandal broke in late 2014 when German broadcaster ARD alleged a number of positive dope tests involving Russian athletes were covered up by IAAF officials.
Several IAAF officials are implicated in covering up Russian doping including Diack's son, IAAF marketing consultant Pape Massata Diack. The others were Valentin Balakhnichev, the IAAF treasurer and Russian Athletics Federation president, and Cisse, who worked for the IAAF as legal adviser. All three agreed to stand down from their positions pending an investigation.
WADA later released a short statement in which it said that the investigations had been prompted by its information.
"WADA is aware of the ongoing criminal investigations relating to sport officials and allegations of corruption and money-laundering, as announced by the French authorities earlier today. These investigations are a result of information passed on by WADA's Independent Commission (IC) to the relevant authorities," the statement read.
"WADA will make no further comment at this time."