The brother of former Colombian President Alvaro Uribe has been arrested for alleged involvement in murders and forced disappearances involving a far-right death squad in the 1990s.

Santiago Uribe was arrested Monday in Medellin. He has long denied any involvement in the murders attributed by a former police officer to the group known as the "12 Apostles." It allegedly plotted scores of murders from an Uribe family's cattle ranch in northern Antioquia state.

Former President Uribe is traveling in the U.S. and has not yet commented. He has long asserted his brother's innocence and accused his successor, Juan Manuel Santos, of trying to smear his conservative political movement.