Police officers arrive at a ranch where a firefight took place on Friday in Tanhuato, state of Michoacan on May 23, 2015.

© 2015 Reuters

(New York) – Mexico should conduct a prompt, thorough, and impartial investigation into the killings on May 22, 2015, in Michoacán state, Human Rights Watch said today. During a three-hour shootout between federal police officers and civilians in the municipality of Tanhuato, 42 civilians and one police officer died, according to official sources.

Federal Police General Commissioner Enrique Galindo said that the officers were responding to gunfire by the civilians. But the fact that 42 civilians were killed while security forces suffered only 1 casualty raises serious questions about whether the use of force was proportionate and lawful, Human Rights Watch said.

“Given Mexican security forces’ poor human rights record, a rigorous and transparent investigation is critically important to determine if indeed there was proportionate use of force during a shootout, and if there were extrajudicial executions,” said Daniel Wilkinson, Americas managing director at Human Rights Watch. “The Attorney General’s Office should take immediate steps to ensure that these crimes are investigated without the delay and negligence that characterized the investigation of the killings in Tlatlaya last June.”

National Security Commissioner Monte Alejandro Rubido told the media that 42 police officers arrived in Tanhuato to investigate an alleged takeover of a ranch by armed “criminals.” He said the officers responded to gunfire from a vehicle, and chased the vehicle until it entered the ranch. Once the officers arrived at the ranch, other people started firing at the officers from inside, he said. More than an hour later, approximately 60 additional police officers arrived, including several who shot at the ranch from a helicopter.

Mexican government officials, including Galindo and Rubido, explicitly denied that the officers had committed extrajudicial executions. Three men who survived surrendered and were detained, and at least 38 weapons were seized, Rubido said.

The Associated Press and local media outlets reported that family members of some of those who died said that one of the bodies had a gunshot in the top of the head, another had bruises in his face and an eye missing, and the teeth of a third person had been knocked inward. People living nearby said most of the shots came from the police helicopter, according to media accounts.

The state attorney general of Michoacán told reporters that the case is being handled by the Attorney General’s Office, but that his office was conducting the preliminary steps of the investigation. The National Human Rights Commission (CNDH) is also investigating.

In June 2014, military personnel opened fire on a group of civilians who were inside an empty warehouse in Tlatlaya, in Mexico state, killing 22 of them. One soldier was injured. Accounts from witnesses and a report by the CNDH said that at least 12 civilians were extrajudicially executed.

State prosecutors detained two of the three surviving witnesses, beat them, repeatedly asphyxiated them with a bag, and threatened them with sexual abuse to force them to confess to having links to people killed in the incidents, and to say that the military was not responsible for the killings, the CNDH reported. The prosecutors also threatened and mistreated a third witness, and forced the three witnesses to sign documents they were not allowed to read, the report said.

The Attorney General’s Office only got involved in the investigation three months later. The office has charged seven soldiers and a lieutenant, but only with the killing of eight people. Moreover, although the CNDH said the Defense Ministry had covered up the crime, the investigation has yet to identify all the military officials involved in the cover-up, a lawyer involved in the case told Human Rights Watch.

“To avoid repeating the investigative fiasco of the Tlatlaya case, the attorney general should immediately reach out to independent and rigorous forensic experts who can provide credibility to her office’s investigations into the killings,” Wilkinson said.