A/HRC/4/48 page 29 20. In Bogotá on 21 March, a university professor who also acted as a political adviser was taking exercise in the National Park when he disappeared. Although the police carried out a lengthy search in the area where he had last been seen, nothing was found until his decomposed corpse was finally located on 23 April. While the authorities claimed that his death was the result of an accident, his relatives and some human rights NGOs pointed out that the remains bore evidence of violent assault. Prosecutor No. 25 of the Human Rights and International Humanitarian Law Unit is investigating this incident as a case of enforced disappearance and murder. 21. In Bogotá on 20 April, a well-known trade union and civic leader disappeared with another person when they were both in San Francisco market place in Ciudad Bolívar. In this case, an NGO and the victim’s family activated the urgent search mechanism for missing persons. 22. Paramilitaries were allegedly responsible, in January 2006, for the deaths of four peasants and the disappearance of another eight in the municipality of Vista Hermosa (Meta). Several of the victims had been arrested a few days earlier by the army, the Attorney-General’s Office and the DAS, but they were set free shortly before their disappearance, attributed to a paramilitary group which demobilized three months later. 23. The Office received information about cases of illegal or arbitrary detention, of both individuals and groups, in the departments of Arauca, Norte de Santander and Putumayo. According to a study carried out by the Office, in six cases which occurred between October 2005 and June 2006 in the departments of Arauca and Norte de Santander, at least 92 persons were arrested and accused of contempt of authority. Of those, 78 were released after periods of detention of between one and nine months. In Puerto Leguízamo (Putumayo) on 11 February, in an operation by the Attorney-General’s Office, nine persons were illegally arrested by army personnel and police officers. 24. The Office also learned of cases of illegal and arbitrary arrest of human rights workers and social leaders, who were accused, without sufficient evidence, of the offence of contempt of authority. In Pamplona (Norte de Santander) on 6 January, members of the CTI from the Attorney-General’s Office and a number of police officers arrested an activist from the Committee for Solidarity with Political Prisoners, which operates under the Protection Programme run by the Ministry of the Interior. 25. In several cases known to the Office, army personnel were involved in arrests carried out without a judicial warrant. In El Tarra (Norte de Santander) on 22 June, members of No. 10 Energy and Transport Plan Battalion arrested a community leader whom they accused of collaborating with the guerrillas. In Barbacoas (Nariño) on 15 October, soldiers from No. 3 Infantry Battalion “José María Cabal” arrested the brother and nephew of a union leader from the village of Guayacana. 26. In some cases, judicial proceedings against people charged with contempt of authority and terrorism were carried out on military premises, from the start and up to the examination stage. This occurred in proceedings initiated by the Attorney-General’s Office in Arauca and Norte de Santander.