EL PASO, Texas >> The shooting that killed 20 people at a crowded El Paso department store will be handled as a domestic terrorism case, federal authorities said as they weighed hate-crime charges against the suspected gunman that could carry the death penalty.

A local prosecutor announced today that he would file capital murder charges, declaring that the alleged assailant had “lost the right to be among us.”

The attack on Saturday was followed less than a day later by another shooting that claimed nine lives in a nightlife district of Dayton, Ohio. That shooter was killed by police. Together the two assaults wounded more than 50 people, some of them critically, and shocked even a nation that has grown accustomed to regular spasms of gun violence.

Investigators focused on whether the El Paso attack was a hate crime after the emergence of a racist, anti-immigrant screed that was posted online shortly beforehand. Detectives sought to determine if it was written by the man who was arrested. The border city has figured prominently in the immigration debate and is home to 680,000 people, most of them Latino.

Using a rifle, the El Paso gunman opened fire on shoppers during the busy back-to-school season.

The attack targeted a Walmart and did not spread to other nearby shopping areas, El Paso police Sgt. Robert Gomez said.

Most victims were inside the store. By this evening, all bodies had been removed from the store and the parking lot, police said. They did not release names or ages, though some families announced that loved ones had been killed.

Despite initial reports of possible multiple gunmen, the man in custody was believed to be the only shooter, police said.

Law enforcement officials identified him as 21-year-old Patrick Crusius from Allen, a Dallas suburb which is a nearly 10-hour drive from El Paso.

The suspect’s grandparents, Larry and Cynthia Brown, issued a statement this evening. A family friend read the statement aloud outside the couple’s home in Allen, KDFW -TV reported.

The Browns said they were “devastated” by the shooting and were praying for the victims. The couple added that while Crusius’ driver’s license shows their Allen residence, he had moved out of the home six weeks ago. Crusius was living with his grandparents while he attended nearby Collin College.

Crusius was arrested without police firing any shots and was jailed without bond, authorities said. There was no immediate indication that he had an attorney.

Gomez said Crusius surrendered after being confronted by officers on a sidewalk close to the scene. Police did not know how many bullets were fired or why the attack stopped.

“We don’t have information on what prompted him to stop firing,” Gomez said.

El Paso Police Chief Greg Allen said the suspect was cooperative and “forthcoming with information.”

Police said they did not know where the weapon was purchased. Allen acknowledged that it is legal under Texas law to carry a long gun openly in a public place.

“Of course, normal individuals seeing that type of weapon might be alarmed,” but before he began firing, the suspect was technically “within the realm of the law,” Allen said.

Relatives said a 25-year-old woman who was shot while apparently trying to shield her 2-month-old son was among those killed, as was her husband. Mexican officials said six Mexican nationals also were among the dead.

Mexico planned to take legal action against whoever sold the gun to the suspect, the country’s foreign minister said. Gun ownership is highly restricted in Mexico, requiring special permits, and gun shops are rare.

President Donald Trump denounced both shootings, saying “hate has no place in our country.” Addressing reporters in Morristown, New Jersey, the president said today that “we’re going to take care” of the problem. He said he’s been speaking to the attorney general, the FBI director and members of Congress and would make an additional statement Monday.

Trump also pointed to a mental illness problem in the U.S., calling the shooters “very seriously mentally ill.”

Authorities searched for any links between the suspect and the material in the document that was posted online, including the writer’s expression of concern that an influx of Hispanics into the United States will replace aging white voters, potentially turning Texas blue in elections and swinging the White House to Democrats.

The writer also was critical of Republicans for what he described as close ties to corporations and degradation of the environment. Though a Twitter account that appears to belong to Crusius included pro-Trump posts praising the plan to build more border wall, the writer of the online document says his views on race predated Trump’s campaign and that any attempt to blame the president for his actions was “fake news.”

The writer denied he was a white supremacist, but the document says “race mixing” is destroying the nation and recommends dividing the United States into territorial enclaves determined by race. The first sentence of the four-page document expresses support for the man accused of killing 51 people at two New Zealand mosques in March after posting his own screed with a conspiracy theory about nonwhite migrants replacing whites.

El Paso Mayor Dee Margo said he knew the shooter was not from the city.

“It’s not what we’re about,” the mayor said at the news conference.

El Paso County is more than 80% Latino, according to the latest census data. Tens of thousands of Mexicans legally cross the border each day to work and shop in the city.

Trump visited in February to argue that walling off the southern border would make the U.S. safer. City residents and Democratic presidential candidate Beto O’Rourke, who is from El Paso, led thousands on a protest march past the barrier of barbed wire-topped fencing and towering metal slats.

O’Rourke, a former Texas congressman, stressed that border walls have not made his hometown safer. The city’s murder rate was less than half the national average in 2005, the year before the start of its border fence. Before the wall project started, El Paso had been rated one of the three safest major U.S. cities going back to 1997.

Trump ordered flags flown at half-staff in memory of the victims of the two shootings.

The shootings in Texas and Ohio were the 21st and 22nd mass killings of 2019 in the U.S., according to the AP/USA Today/Northeastern University mass murder database that tracks homicides where four or more people killed — not including the offender.

Including the two latest attacks, 125 people had been killed in the 2019 shootings.

Since 2006, 11 mass shootings — not including Saturday’s — have been committed by men who are 21 or younger.