GEORGETOWN, Guyana — A Colombian national sanctioned by the United States Treasury Department for his role in a transnational drug-trafficking network operating in Guyana has been detained by local authorities. The Guyana Police Force confirmed that 33-year-old Yeison Andres Sanchez Vallejo was arrested on Tuesday after a Lethem-bound minibus was stopped at the Kurupukari checkpoint. Officers discovered that his passport carried an immigration stamp marked “Refused Leave to Land” and detained him for illegally entering Guyana.
Under Guyanese immigration procedures, the “Refused Leave to Land” (RLL) stamp indicates that a foreign national has been denied legal entry into the country due to security or immigration concerns. Possession of such a document means the individual should not be within Guyana’s borders. The police said Sanchez Vallejo was immediately arrested and remains in custody assisting investigators, though authorities have not disclosed how long he has been in the country or his intended destination.
According to the U.S. Department of the Treasury’s Office of Foreign Assets Control (OFAC), Sanchez Vallejo—also known as “Andreas” and “Blacks”—is one of several individuals identified as part of a cocaine-trafficking network operating in Guyana’s Barima-Waini region. The area has been described by U.S. officials as a key transshipment route for cocaine moving from Colombia and Venezuela to the United States, Europe, and the Caribbean.
The June 2025 OFAC report lists Sanchez Vallejo alongside several others: Manuel Salazar Gutierrez, also known as “Manguera” and “Orejon”, a Colombian national identified as a senior operator in the network; Mark Cromwell, known as “Diamond” or “Demon”; Himnauth Sawh; Randolph Duncan, also called “Rudolph Duncan”; and Paul Daby Jr., also known as “Randell.” All are Guyanese nationals except Gutierrez, who is Colombian.
The U.S. Treasury Department notes that these traffickers exploit illegal airstrips, maritime routes, and remote jungle corridors across Guyana to move cocaine shipments, often using narco-submarines and underground bunkers to conceal cargo. Their operations reportedly extend through networks spanning Guyana, Suriname, Venezuela, and Colombia. The Guyana Police Force said investigations into Sanchez Vallejo’s presence in the country are ongoing and may involve coordination with international partners.