A dozen state police officers have been arrested in Mexico for allegedly killing 19 people, including Guatemalan migrants, whose bodies were found shot and burned near the US border late last month, authorities announced.
Tamaulipas state attorney general Irving Barrios Mojica said all 12 officers were in custody and face charges of homicide, abuse of authority and making false statements.
The killings revived memories of the gruesome 2010 massacre of 72 migrants near the town of San Fernando in the same gang-ridden state, but those killings were done by a drug cartel, while it is likely many people will find it more shocking that the January 22 killings were allegedly carried out by police.
"In the aforementioned acts of January 22, at least 12 state police officers participated," Mr Barrios Mojica said.
He did not say what motive the officers might have had, although corrupt local and state police in Mexico are often in the pay of drug cartels.
The gangs often charge migrant smugglers for crossing their territory, and kidnap or kill migrants whose smugglers have not paid or paid a rival gang.
The bodies were found piled in a charred pick-up truck in Camargo, across the Rio Grande from Texas, in an area that has been affected for years by turf battles between the remnants of the Gulf cartel and the old Zetas cartel.
Authorities have said four of the dead have been identified so far - two Guatemalans and two Mexicans. Their names have not been released by officials, but relatives of one of the dead Mexicans said he worked as an immigrant trafficker.
Of the 19 bodies examined by experts, 16 were found to be males, one was confirmed as female and the two others were so badly burned their gender had not yet been determined.
The forensic results confirmed the fears of families in a rural Indigenous farming community in Guatemala who have said they lost contact with 13 migrants as they travelled toward the US.
The truck holding the bodies had 113 bullet impacts, but authorities were confused by the fact that almost no spent shell casings were found at the scene.
Initially, that led investigators to speculate the shootings may have taken place elsewhere, and the truck driven to the spot where it was set on fire, but Mr Barrios Mojica said the officers charged in the killings knew their shell casing might give them away, and probably picked them up.
"There is growing force behind the hypothesis that the crime scene was altered, due to the absence of casings," he said.
Mr Barrios Mojica said the truck carrying the victims was apparently part of a larger convoy of vehicles transporting migrants from Guatemala and El Salvador to smuggle them across the US border. He said the trucks also carried armed men to provide protection.
Read more:Fleeing poverty and violence in Honduras - a migrant's journey to the US
