At least 20 people are dead after a mass shooting at a shopping center in El Paso, Texas, on Saturday, August 3. Police said another 26 were injured, and that a suspect is in custody.

Governor Greg Abbott called it “one of the most deadly days in the history of Texas.”

The rampage came six days after 15 people were shot, three of them fatally, at the Gilroy Garlic Festival in Northern California, and a week after 12 people were shot, one of them fatally, at a block party in Brooklyn, New York. Within 24 hours after the El Paso shooting, a gunman in Ohio had killed nine people and injured 27 others in Dayton.

The first 911 calls came in at about 10 a.m. and reported a shooting at a Walmart near the Cielo Vista Mall. Police responded in six minutes.

Shortly afterward, the El Paso Fire Department said emergency workers had transported at least 18 wounded people to local hospitals. The Washington Post reported that, “Witnesses said Good Samaritans used their own cars to transport victims to hospitals.”

University Medical Center of El Paso, which received 11 victims, said a 4-month-old was among those treated. A second hospital received another 11 victims, ranging in age from 35 to 82.

The shooting occurred just before the start of a new school year and ensnared throngs of shoppers looking to take advantage of back-to-school sales. Security camera footage that the police confirmed shows the gunman depicts a young white man wearing hearing protection and wielding what looks to be an AK-47-type rifle.

Media outlets reported that the gunman has been identified by police sources as 21-year-old Patrick Crusius of Allen, Texas. In an online screed attributed to the gunman, the author rails against a “Hispanic invasion of Texas” and the changing demographics of the United States. The writer also praises the New Zealand mosque gunman.

Federal investigators said Sunday that they’re treating the shooting as a domestic terror incident, and considering levying federal hate crimes charges against the gunman, as well as federal gun charges that carry the death penalty.

In an FBI report obtained this week by Yahoo News, the agency says “anti-government, identity-based, and fringe conspiracy theories” are a domestic terrorist threat, and cited the Pittsburgh synagogue shooting and Sandy Hook denialism as examples.

The author of the screed says he spent a month planning the attack and debates which gun and ammunition to use. He says he used a variant of an AK-47, but notes that it “overheats massively after about 100 shots fired in quick succession.”

At least one concealed gun carrier at the scene was armed but didn’t open fire. Glendon Oakley Jr., a 22-year-old soldier stationed at Fort Bliss, was in a nearby Foot Locker when gunfire rang out. He brandished his Glock, but says he came upon a group of about a dozen children and shepherded them to safety.

More people were shot in the mall rampage than were shot in the entire city of El Paso in all of 2018. According to Gun Violence Archive, there were 20 gun fatalities last year in El Paso, which is one of the safest cities in the United States.

Democratic presidential candidate Beto O’Rourke, who grew up in El Paso and represented the city in Congress, said: “I am incredibly saddened, and it is very hard to think about this. But El Paso is the strongest place in the world.”