Question: Jorge Julio López disappeared after testifying against the Argentine police officer who worked in what force during the 1970s?
Context: The Treaty Three Police Service (T3PS) in Ontario began as the Treaty #3 Policing Initiative in August 1999 as directed by the Executive Council of Grand Council of Treaty 3.  It officially began operation on August 5, 2003, and became Canada’s newest First Nation self-administered police service.  Members of Treaty Three Police are appointed as First Nations Constables by the Commissioner of the OPP pursuant to s.54 of the Police Services Act.  They have the powers of a police officer for the purpose of carrying out duties specified in their appointments and under federal law have the powers and protections of peace officers.  Because First Nations Constables are not police officers as defined by the Police Services Act, their status in law is different but equal to that of a police officer.  The jurisdiction of the Treaty Three Police Service includes all signatory Treaty Three First Nations (The Paypom Treaty) previously policed by the OPP administered First Nations Policing Program.  The OPP are mandated to provide policing on a reserve, village or any other area not currently under a policing agreement.  All operations save major crimes are investigated by Treaty Three First Nations Constable patrol officers and/or the T3PS Crime Unit.  The Service exists with the unanimous agreement of the signatory Band Councils or Band Chiefs.  Unlike police forces in cities and towns, the Treaty Three Police Service is not required to provide all the regular services of a police force but does provide virtually everything needed (or requests additional OPP resources, e.g. K9 Unit). Special police (also see auxiliary police) usually describes a police force or unit within a police force whose duties and responsibilities are significantly different from other forces in the same country or from other police in the same force, although there is no consistent international definition.  A special constable, in most cases, is not a member of a special police force; in countries in the Commonwealth of Nations and often elsewhere, a special constable is a voluntary or part-time member of a national or local police force or a person involved in law enforcement who is not a police officer but has some of the powers of a police officer. A police officer, also known as a policeman, policewoman, police agent, or a police employee is a warranted law employee of a police force.  In most countries, "police officer" is a generic term not specifying a particular rank.  In most police departments of the United States, "police officer" or "officer" is also the rank held by a regular police officer (i.e. one without supervisory duties).  In some nations the use of the rank "officer" is legally reserved for military personnel. Miguel Osvaldo Etchecolatz (born 1 May 1929) is a former senior Argentine police officer, who worked in the Buenos Aires Provincial Police during the first years of the military dictatorship of the 1970s.  Etchecolatz was deeply involved in the "anti-subversion operation" known as the National Reorganization Process ("El proceso").  He was first convicted in 1986 of crimes committed during this period, but passage that year of the "Ley de Punto Final," which created amnesty for security officers, meant that he was released without a sentence.  In 2003 Congress repealed the law, and the government re-opened prosecution of crimes during the Dirty War. Law enforcement in the Pitcairn Islands is the responsibly of the Pitcairn Islands Police, the smallest British police force, which has just two constables.  In the aftermath of child sex revelations (see below) the force did briefly number five constables including Ministry of Defence Police officers on temporary secondment.  Historically, and until 2000, a Pitcairn Island resident was appointed as the island group's sole police officer, and also acted as immigration and customs officer.  From 2000 to 2015, the combined police, immigration, and customs role was held by a series of foreign professionals on short-term secondment.  In 2015 the Pitcairn Government website announced that both previous systems would be employed alongside each other, with one local island police officer and one foreign police officer on secondment, working together. Mario Oscar Ferreyra, better known as Malevo (June 17, 1945 – November 21, 2008) was an Argentine police chief.  Being a police officer during the Proceso de Reorganización Nacional, he participated in the Dirty War, fighting against left-wing guerrilla groups in Tucuman province.  After the return of democracy, he would become the chief of Tucumán Provincial Police.  In this position, Ferreyra became involved in the dubious death of a number of supposed criminals.  He would later be prosecuted and discharged from the force.  He shot himself in 2008, when facing his imminent arrest, and his suicide was broadcast live on national TV. Rodolfo Almirón Sena (February 17, 1936 – June 5, 2009) was a former Argentine police officer and a leader of an extreme right-wing death squad known as the Triple A, operating in Argentina from 1973 to 1976 against the left-wing of Peronistas and other political dissidents.  The group is held responsible for 1,500 murders of government opponents during the terms of Juan and Isabel Perón. Jorge Julio López (born 1929, in Buenos Aires Province, Argentina) is an Argentine retired bricklayer, who was kidnapped during the National Reorganization Process, and disappeared again during the democratic government of President Néstor Kirchner after testifying in trial against Dirty War criminal Miguel Etchecolatz. Arcadio Julio López (born September 15, 1910, date of death unknown) was an Argentinian football defender who played for Argentina in the 1934 FIFA World Cup.  He played for many clubs, including Club Atlético Lanús (1931-1934 and 1942), Club Sportivo Buenos Aires (1934), Ferro Carril Oeste (1935-1937) and Boca Juniors (1938-1942). Phajol Moolsan (Thai: ผจญ มูลสัน ; rtgs: "Phachon Munsan" ; born September 13, 1968) is a Thai boxer.  At the 1988 Summer Olympics he won a bronze medal in the men's Bantamweight category, together with Jorge Julio Rocha of Colombia.
Answer: Buenos Aires Provincial Police