The watchdog said the deaths occurred following an operation in January to crack down on vigilantes in the city of Apatzingan in the heart of the troubled Hot Land region of the state of Michoacan.
Former rural police officers were protesting their disbanding and lack of pay when Mexican federal police stormed their encampment and proceeded to execute at least 16 people, according to this special report.
After the missing 43 and the massacre at Tlatlaya, the country is now facing a third likely state-led mass killing in less than a year. A journalist says federal police killed 16 civilians in Apatzingan, Michoacan.
Servando Gomez Martinez, known as "La Tuta," had been isolated in recent months under pressure from federal forces and the community militias known as autodefensas.
Alfredo Castillo was sent to Michoacan one year ago, on personal orders from President Enrique Peña Nieto. Today, local cartel chief 'La Tuta' remains at large and self-defense militias are battling each other in fatal shootouts.
Troops marched into Michoacan in 2006, then federal forces came again in 2014, in response to a growing militia movement. A year after that, violent attacks, extortion, and impunity pervades across the "Hot Land" region.
The son of the founder of the first civilian militia in Michoacan is among the victims. One parish priest tells us: "We used to know who the bad guys were. Now we don't."
Dr. Jose Manuel Mireles, the symbolic leader of the vigilante movement in Michoacan, faces drugs and weapons charges after his arrest.