The Colombian President has said that his forces have arrested a former peace negotiator for the FARC, the ex-rebel-group-turned-political-party.
Juan Manuel Santos said that Seusis Hernandez could be extradited to the United States after his arrest on drug trafficking charges.
"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.
Mr Hernandez was due to take office in congress in July.
However, Attorney General Nestor Humberto Martinez claimed that he conspired to export ten tonnes of cocaine worth $320m in street value to the US.
The landmark peace deal between the FARC and Mr Santos's government was signed in November 2016, putting an end to a half century of conflict.
Since then, the FARC has disarmed and transformed itself into a political party, swapping its crossed-rifles emblem for a red rose.
Ten of its members were given allotted seats in Congress.
Some dissident members of the FARC are said to have turned to drug trafficking and other criminal endeavors.
Under the peace accord, repentant FARC fighters were required to confess their wartime crimes and pay reparations to victims to avoid jail.
However, they could still be arrested for any crimes they committed after the deal.
