According to initial reports, Mario Medina Garzón, 37, was arrested at the Tapachula International Airport on November 11 when authorities found fake passports for the former governor of Veracruz Javier Duarte and his wife Karime Macías.
Federal Police have increased surveillance on the Mexico-Guatemala border to prevent the escape of the former official who is wanted for money laundering and organized crime.
Mario Medina, who is believed to be the cousin of Javier Duarte's wife, said the passports were to be delivered to the former governor of Veracruz so he and his wife could leave to Guatemala soon as possible.
Last week, the Attorney General's Office (PGR) offered a reward of 15 million pesos (US$730,000) for information leading to the arrest of Duarte.
The PGR released Mario Medina as the falsification of documents is not a felony.