CARACAS (Reuters) - Venezuela’s state prosecutor said on Sunday it would charge 11 members of the military for responsibility in the death of 12 civilians following a security raid last month in the violent country’s coastal state of Miranda.

Leftist President Nicolas Maduro last year launched a security campaign known as “Operation to Free the People,” or “OLP” to fight crime and gangs in Venezuela, which has one of the world’s highest murder rates.

Rights groups and residents say authorities have murdered innocent people, arrested thousands, and destroyed private property without legally-mandated court orders.

In the Miranda case, 12 bodies were discovered between Friday and Saturday in a mountainous area of the state, the state prosecutor’s office said in a statement.

“The state prosecutor will attribute several crimes to the arrested officials, including the violation of fundamental rights,” the statement read, adding that the 11 members of the military included a lieutenant colonel.

Local media reported the bodies were discovered in a mass grave.

Calling it a massacre, the opposition slammed the case as a further example of oppression and violence from a government they say has swerved into a dictatorship.

Opposition lawmaker Delsa Solorzano, who presides the National Assembly’s internal affairs commission, said accounts from family members indicate the men were initially detained and “subject to forced labour” between Oct. 15 and Oct. 17.

When relatives returned to visit them on Oct. 19 to bring food and clothes, the lieutenant colonel being charged told them the detainees had been transferred to a military school, Solorzano added.

“They went to (the military school), and they’re told that no, it’s been over 15 days since they’ve received any transfers,” said Solorzano, adding that accounts suggest two people are still missing.

The Defense Ministry said in a statement that it condemned the deaths.

“This type of isolated case goes against the nation and the military’s legal norms and does not represent in any way the professionalism and humanist vocation that characterizes the soldiers of the fatherland,” said minister Vladimir Padrino.

The Information Ministry did not immediately respond to a request for further details.