(CNN) -- Ecuadorian President Rafael Correa will face an investigation into whether his presidential campaign received money from Colombian leftist guerrillas, Ecuador's attorney general's office said.
The investigation was initiated based on a report by the London-based International Institute for Strategic Studies. This month the organization released a book-length dossier that examines in detail the relationship between Venezuela, Ecuador and the Revolutionary Armed Forces of Colombia guerrilla group -- commonly known as the FARC.
The institute spent two years researching 30 years' worth of strategic documents and recent e-mails belonging to FARC leader Luis Edgar Devía Silva, whose nom de guerre was Raul Reyes. He was killed in a 2008 raid, leaving behind the digital records.
In 2006, FARC contributed about $400,000 to Correa's campaign -- with $100,000 apparently directly from the rebel group and $300,000 more from its allies, the report alleged.
Nigel Inkster, director of the institute, told CNN that those allies were drug traffickers.
"Correa almost certainly approved the use of these funds in his campaign, but this did not translate into a policy of state support for the insurgents during the brief period between Correa's inauguration and Reyes's death," the study said. "Although the death of Reyes provoked a serious breach in relations between Colombia and Ecuador -- ironically a key FARC strategic objective -- it also interrupted FARC's burgeoning relationship with Quito (the Ecuadorian capital). There is no evidence that the relationship has since prospered."
Correa's current and former ministers have said that there is no truth to the allegations made in the report.