Look into US involvement with the Tlatelolco massacre. It was effectively order by the US. If they are willing to do that to someone else they will eventually be willing to do that to you. The death count you see on wikipedia is almost certainly an understatement they locked them in a square and shot at them like fish in a barrel

That in response to Mexican government concerns over the security of the Olympic Games, the Pentagon sent military radios, weapons, ammunition and riot control training material to Mexico before and during the crisis.

The Olympia Battalion members wore white gloves or white handkerchiefs tied to their left hands to distinguish themselves from the civilians and prevent the soldiers from shooting them

Captain Ernesto Morales Soto stated that “immediately upon sighting a flare in the sky, the prearranged signal, we were to seal off the aforementioned two entrances and prevent anyone from entering or leaving.”

The soldiers responded by firing into the nearby buildings and into the crowd, hitting not only the protesters, but also watchers and bystanders. Demonstrators and passersby alike, including students, journalists (including Italian reporter Oriana Fallaci), and children, were hit by bullets, and mounds of bodies soon lay on the ground.

Olympia Battalion members pushed people and ordered them to lie on the ground near the elevator walls. People claim these men were the people who shot first at the soldiers and the crowd.

Video evidence also points out that at least two companies of the Olympia Battalion hid themselves in the nearby apartment buildings and set up a machine gun in an apartment in the Molino del Rey Building

Thousands of students gathered in the square and, as you say, the government version is that the students opened fire. Well, there’s been pretty clear evidence now that there was a unit that was called the Brigada Olímpica, or the Olympic Brigade, that was made up of special forces of the presidential guard, who opened fire from the buildings that surrounded the square, and that that was the thing that provoked the massacre.

U.S. officials stood resolutely by Díaz Ordaz after Tlatelolco

in a review of “contingency scenarios” drafted by the U.S. Embassy in November, the ambassador urged Washington to be prepared to grant financial assistance and economic support packages to Mexico in the event of continued or increased student violence, as a way of showing U.S. support for the regime.

Finally, not one document declassified by the U.S. government discusses at any length evidence that government agents operating as snipers from the windows of the Tlatelolco apartment complex may have initiated the massacre of October 2