Reuters New Media Wednesday February 4 5:28 PM EST Amnesty Closed Colombia Office Due to 'threat' BOGOTA (Reuters) - Amnesty International said Wednesday that threats against its personnel had forced it to shut down its office in Colombia -- two months after the killing of two human rights workers in the capital. In a brief statement explaining the quiet closure of its Bogota office in July, the London-based human rights group did not reveal the origin of the "series of threats" it said its workers had received. But it said they came "within the context of the current campaign of threats affecting the community of human rights defenders in the country" and were taken seriously enough that Amnesty's executive committee chose to close the office indefinitely. Mario Calderon and his wife Elsa Alvarado, investigators with a Jesuit-backed human rights group known as Cinep, were machine gunned to death in their Bogota apartment last May in a killing that had all the hallmarks of a right-wing death squad. Seven suspects have been arrested in connection with the case, including two alleged gunmen nabbed Tuesday in Medellin, but authorities have been tight-lipped about who might have ordered the killings, which prompted an international outcry. Right-wing paramilitary groups and senior Colombian military officials often bridle at the work of leading human rights groups, saying they put too much emphasis on official cases of abuse and too little on crimes committed by the country's leftist guerrillas. The military is also extremely sensitive to allegations, such as those made by the U.S. State Department in its annual human rights report last week, of links between paramilitaries and the army. Because none of its local personnel was actively involved in investigating human rights abuse in Colombia -- which has one of the most dismal rights records in the hemisphere -- Amnesty said the work it does in the country through international monitors would continue unabated. "Amnesty International has not diminished or suspended its work in favor of human rights in Colombia," said the statement, which was written in Spanish. "On the contrary, the human rights crisis in the country continues to be a very high priority for Amnesty International."