U.S. President Donald Trump slammed 2020 Democratic presidential candidate Beto O’Rourke for having a “phony” nickname to “indicate Hispanic heritage” and told the former El Paso congressman to “be quiet!”

O’Rourke, whose birth name is Robert, but was called Beto since childhood by his parents, responded quickly to Trump’s taunt. O’Rourke wrote, “22 people in my hometown are dead after an act of terror inspired by your racism. El Paso will not be quiet and neither will I.”

The massacre that killed 22 people at a Walmart in El Paso struck a city that has long been the cradle of Mexican American culture and immigration and suffered through bloody episodes of racial violence in the past.

The white gunman apparently wrote an anti-Hispanic rant before opening fire with an AK-47-style rifle on Walmart shoppers — many of them Latino — rattling a city that has helped shape Mexican American life across the U.S. for generations.

In the last year, El Paso has garnered attention because of the rapid rise of migrants from Central America coming to seek asylum. The city also has been a testing ground for immigration enforcement, with the government spending millions of dollars on agents, barriers and border security technology and equipment.

President Donald Trump, who is visiting the city Wednesday, has cited El Paso’s crime rate as proof for why his border wall is needed, despite FBI statistics that show the city routinely has a violent crime rate below the national average. Crime statistics also show the city to be safer than other municipalities the same size in population.

Why the alleged shooter chose El Paso as his target remains a mystery. But the online rant investigators have attributed to him speaks of a “Hispanic invasion of Texas” and theories of non-white immigrants replacing whites.

Many Mexican Americans in Los Angeles, New Mexico, Texas, Colorado and beyond can trace their families’ roots to El Paso, sometimes called the “Ellis Island” of the border. The city served as a port of entry where immigrants from the interior of Mexico had to come to gain entry into the United States before World War II.

Mexican Revolutionary leader Pancho Villa visited the city. Country artist Marty Robbins famously sang in 1959 about falling “in love with a Mexican girl” here. It is the birthplace of civil rights lawyer Oscar Zeta Acosta, journalist Ruben Salazar and poet Pat Mora. The city is also a geographic center of sorts for Mexican Americans, sitting about the same distance to Los Angeles as it is to Houston.

“El Paso has a deeper history than what you see on the news,” said Sergio Troncoso, an El Paso-born novelist who now lives in New York City. “That manifesto shows that white nationalists continue to reduce El Paso to immigration and a place of foreigners. It’s so much more than that.”