Colombia's peace agreement is at "its most critical point" after the detention of Jesus Santrich, a Congress member-elect representing the recently formed political party Revolutionary Alternative Forces of the Commons, or FARC, for extradition to the United States over alleged drug trafficking, the organization's number two, Ivan Marquez told reporters Tuesday.
Hernandez will remain in custody until the USA request for extradition is formalized, Martinez said.
He was picked up Monday at a Bogota residence on charges filed in a NY federal court alleging he conspired with three others to smuggle several tons of cocaine into the USA with a wholesale value of $15 million (£10.6 million), or a street value of $320 million (£226millon).
He was accused of meeting cocaine buyers in his Bogota residence on November 2 to discuss the shipment.
Santrich was a leader in the now disarmed Revolutionary Armed Forces of Colombia, FARC, guerrilla movement, and was one of the top negotiators for the leftist group during the 2016 peace process with the Colombian government.
"If due process is fulfilled - and if there is irrefutable evidence - then there are grounds for extradition for crimes committed since the signing of the (peace) accord, and I will not stay my hand in authorising that", Mr Santos said.
The accord allows for rebels to be spared from prosecution if they lay down their arms and confess their war crimes to special peace tribunals.
Santrich was one of FARC's key participants in the peace negotiations that eventually led to the peace agreement with the Colombian government in 2016.
More than 100 former rebels and FARC sympathizers gathered late Monday outside the heavily guarded prosecutors' bunker where the 51-year-old Hernandez was being held to demand his release.
"The peace process is in a critical moment and is in jeopardy of failing", Marquez said, reaffirming that the FARC's commitment to a process that has led to the demobilization of nearly 7,000 fighters "has no return".
Waving white flags emblazoned with the red rose symbol of the former rebels" political movement, some shouted "freedom' and denounced what they called an act of judicial sabotage by the government and its US backers.
However, they could still be arrested for any crimes they committed after the deal.
"The construction of peace requires the absolute commitment and respect for the law and the accords", Santos said.
Some dissident members of the FARC are said to have turned to drug trafficking and other criminal endeavors.
The FARC long funded their insurgency by leveling a "war tax" on cocaine moving through territory the rebels dominated.
"Like addicts they just can't quit the business", he added.