AlQa'dah 25, 1436, September 09, 2015, SPA -- Guatemalan ex-president Otto Perez Molina was formally charged Tuesday with criminal association, corruption and fraud in connection with a customs fraud investigation, according to dpa. Perez Molina, 64, a retired general who had been president since 2012 and resigned last week, has denied the allegations. The court "believes there is sufficient reasonable evidence" to suggest Perez Molina may have committed the crimes, though the judge stressed that no wrongdoing has so far been proved. Guatemalan prosecutors and a UN commission believe the former president led the scheme known as "La Linea," which allegedly helped importers avoid millions of dollars in customs fees in exchange for bribes. Prosecutors think the ring was active from at least May 2014 to April 2015. The Guatemalan Congress accepted Perez Molina's resignation Thursday and appointed Vice President Alejandro Maldonado to fulfil his presidential mandate ending in January. Perez Molina has been detained since Friday. In recorded conversations played in court, Perez Molina's former vice president, Roxana Baldetti, who was arrested last month, appeared to refer to him as "chairman of the company," "number 1" and "owner of the estate."