EL PASO, TEXAS (CBSDFW.COM) — The El Paso district attorney will the seek the death penalty for Patrick Crusius, who is suspected of killing at least 20 people and injuring dozens more near a shopping mall on Saturday, officials said.

At a news conference Sunday, District Attorney Jaime Esparza announced that the 21-year-old will face a capital murder charge, which makes him eligible for the death penalty.

The U.S. Attorney’s Office is also investigating the mass shooting as a domestic terrorism case and that it will also seek federal hate crime charges against Crusius. A manifesto was found on the internet Saturday that authorities investigated as being written by Crusius. In it, the writer claimed “the Hispanic invasion of Texas” as a motivation for the attack.

Dozens of victims, including children, were reported from the shooting near Cielo Vista Mall Saturday afternoon in the largely Latino community near the U.S.-Mexico border. Many of the victims were shot at a Walmart, according to police.

The 21-year-old was found to be a native of North Texas and had resided in the Collin County city of Allen. CBS 11 News also learned that he had attended Liberty High School in Frisco but later transferred to Plano Senior High School, where he graduated in 2017. Collin College also acknowledged that he was enrolled in that school from fall 2017 to spring 2019.

Patrick Crusius mugshot

On Saturday, law enforcement officials from the FBI, Texas Department of Public Safety and the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives could be seen outside of a home in Allen that had possible connections to Crusius. Neighbors in the area said an older couple lives at the home.

Officials familiar with El Paso were shocked that a shooting of this caliber took place as they claim the city has always been safe.

“The loss of life is so great. We’ve certainly never seen this in our community. We are a very safe community. We pride ourselves on the fact that we’re so safe. And certainly this community is rocked and shocked and saddened by what has happened here,” Esparza said on Sunday.

“We will hold him accountable,” he added.

John Bash of the U.S. Attorney’s Office said the case will be treated as domestic terrorism as the shooting meets the definition of intimating a civilian population.

“We are treating it as a domestic terrorism case. And we’re gonna do what we do to terrorists in this country, which is deliver swift and certain justice,” Bash said.