The arrest stokes worries from the US and worldwide analysts that the FARC and other guerrilla groups putting down their weapons will not be able to quit overseeing the illicit, underground industries involving drugs, timber, and gold in Colombia.
A day after the arrest of Seuxis Hernandez, best known by his alias Jesus Santrich, conservative opponents of the peace accord, including the front-running presidential candidate, urged authorities to investigate other members of the disbanded FARC rebel army for any continued involvement in the drug trade.
A USA indictment accuses Santrich and three others of conspiring to distribute 10 metric tons of cocaine with a wholesale value of $15 million in the United States and purporting to have access to drug labs and US -registered planes for transport.
FARC leaders and soldiers were controversially granted amnesty as part of Colombia's peace deal.
"This is the worst moment that the peace process has gone through", said the former FARC official Iván Márquez, according to the Associated Press. "This is what the Colombian people demand". They allegedly discussed their access to coca fields, cocaine laboratories and US -registered aircraft to smuggle the drugs.
Hernandez is a member of the political party Fuerza Alternativa Revolucionaria del Comun (Farc) - the party that emerged after rebel group Revolutionary Armed Forces of Colombia (FARC) was dismantled.
The arrest stems under a week before President Donald Trump is set to go to Bogota for discussions with Santos by which USA claims that Colombia's long standing support for the drug war flagged during peace talks is expected to feature prominently.More news: Spymasters prepare for US-NK summit
A USA grand jury in the Southern District of NY indicted Hernandez, known by his nom de guerre Jesus Santrich, and three others last week, Martinez said.
The Colombian government signed a peace agreement with the FARC on November 2016.
With regards to the accord, rebels who put their weapons down and also confess their war offenses to exclusive peace tribunals should be spared jail time plus extradition.
"The senior leadership never cut ties to the cocaine production that earned them billions of dollars as an insurgence", said Douglas Farrah, a senior visiting fellow at the National Defense University who has testified to U.S. Congress on the FARC's criminal ties.
Even the FARC extended financed their insurgency by leveling a "war tax" on cocaine proceeding through land the rebels dominated.
But the rebels always denied direct involvement in the business itself and rebel peace negotiators in 2013 denounced drug trafficking as a "scourge" that has "contaminated" the worldwide financial system and generated a global health crisis.
'Like addicts they just can't quit the business, ' he added.