The vehicle, which belonged to the National Unit of Protection, was on a road connecting the towns of Campoalegre and Hobo near Cali, Colombia Reports said Tuesday.
The same group of hooded men is believed to have set fire to a public bus on Sunday after it tried to use a different route between the same communities. The gang told the passengers to get off before torching the vehicle.
Government soldiers taken captive during the weekend were released Monday by protesting farmers in southwest Colombia, Gov. Temistocles Ortega of the state of Cauca said Tuesday.
The soldiers' release came after mediation by the United Nations.
They were detained while waiting at a roadblock put up by protesters.
The mayor of Bogotá has said "criminal gangs" have infiltrated protest groups. He blamed the criminal gangs for violence that erupted in the city Thursday that resulted in two deaths and 200 injuries.
The nationwide protests began Aug. 19.