El Paso, Texas (CNN) Federal authorities are treating the El Paso mass shooting as a case of domestic terrorism, the US Attorney for the Western District of Texas said Sunday.

The Justice Department is also "seriously considering" bringing federal hate crime and federal firearm charges, which carry a possible death penalty, US Attorney John Bash said in a news conference.

The case appears to meet the statutory definition of domestic terrorism, Bash said. Saturday's shooting at an El Paso Walmart -- which left at least 20 people dead and 26 injured -- "appears to be designed to intimidate a civilian population, to say the least," he said.

"We're going to do what we do to terrorists in this country, which is to deliver swift and certain justice," Bash said.

The suspect was charged Sunday with capital murder and was being held on no bond, El Paso Police Sgt. Robert Gomez told reporters Sunday evening. The suspect has been cooperating with investigators, he said.

The suspect was arraigned overnight Saturday, Gomez said.

Authorities are investigating a racist, anti-immigrant document they believe was posted by a man who opened fire Saturday morning, shortly after 10:30 a.m. local time.

Authorities have not publicly identified the shooter, but three sources told CNN the suspect is 21-year-old Patrick Crusius of Allen, Texas. The sources were two federal officials and one state official.

Crusius was arrested in the Walmart parking lot, a law enforcement official told CNN. He was in a vehicle in the parking lot and saw responding marked law enforcement units. The suspect then got out of his vehicle unarmed and walked over to law enforcement vehicles where he was arrested without incident, the official said.

People embrace during a vigil for victims of the shooting Saturday, August 3, 2019, in El Paso, Texas.

Crusius' grandparents released a statement Sunday that was read to reporters by a family spokesman who did not want to be named.

"We are devastated by the events of El Paso and pray for the victims of this tragedy. Patrick Crusius is our grandson. He lived with us in our house in Allen, Texas while he attended junior college at Collin County College. He moved out six weeks ago and spent a few nights here while we were out of town. His drivers license and mailing address were at our house in Allen — that connection has made us the focus of media," the spokesman said, reading from the statement. "We are talking only to law enforcement agencies and will not be making further statements to the media. We request the media to honor our privacy."

Authorities have not released the identities of the victims. Investigators are still in the process of identifying them and notifying next of kin, Gomez said.

All of the bodies have been removed from the Walmart and taken to the medical examiner's office, he said.

The shooting was limited to the Walmart and the store's parking lot, Gomez said, despite early reports that an incident had occurred at the nearby Cielo Vista Mall.

Racist 'manifesto' posted on 8chan

About 20 minutes before the shooting started, a post on the online message board 8chan believed to be from the suspect laid out a dark vision of America overrun by Hispanic immigrants. The 2,300-word document, which police called a "manifesto," was attached to a post that said, "I'm probably going to die today."

The writing is filled with white supremacist language and racist hatred aimed at immigrants and Latinos. It blames immigrants and first-generation Americans for taking away jobs.

The writer cited a fear that an influential Hispanic population in Texas would make the state a "Democratic stronghold." But the writer also said "the Republican Party is also terrible" because the GOP is in his mind pro-corporation, which could lead to more immigration.

The writer of the document said they had held these beliefs for years before Donald Trump was elected President.

It took less than a month to plan the shooting, according to the four-page document.

Patrick Crusius

El Paso County had an estimated population of 840,000 people as of July 2018, according to the US Census Bureau . An estimated 83% were Hispanic or Latino.

Saturday's shooting is at least the third atrocity this year where a shooting suspect is thought to have posted to 8chan in advance of an attack

Before the mass shooting in Christchurch, New Zealand , in March, an account believed to belong to the gunman posted a link to an 87-page white nationalist manifesto on Twitter and 8chan.

And 73 minutes before the deadly shooting at Congregation Chabad synagogue in Poway, California, in April, someone identifying himself as the suspect in that attack posted a link to a hate-speech-filled manifesto hyperlinked on 8chan.

Fredrick Brennan, who created of 8chan but no longer owns it, spoke to CNN Sunday and said the problem with the website is "the current administrators are running it in a way that is indefensible."

"If it's going to keep on like this it should be shut down," Brennan said. "I don't want to pile on but they are not doing anything to solve this. They should at least shut down the board for a week or a month after something like this. They are letting their users incite violence."

Cloudflare, a San Francisco-based company that provides internet infrastructure services to 8chan to keep it online, announced Sunday night it would stop providing support for the website in light of the mass shootings in El Paso and Dayton, Ohio.

"The rationale is simple: they have proven themselves to be lawless and that lawlessness has caused multiple tragic deaths. Even if 8chan may not have violated the letter of the law in refusing to moderate their hate-filled community, they have created an environment that revels in violating its spirit," Matthew Prince, Cloudflare CEO wrote in a blog post Sunday evening.

It is possible 8chan may still be able to stay online using a Cloudflare competitor.

8chan then tweeted there might be downtime while the site works to find a solution over the next 24 to 48 hours.

A week bookended by shootings

Photos: In photos: Deadly shootings in El Paso and Dayton El Dorado High School students attend a ceremony Wednesday, August 7, honoring those who died in the mass shooting in El Paso, Texas. Hide Caption 1 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Demonstrators in Dayton, Ohio, protest the visit of President Donald Trump on August 7. Trump visited both Dayton and El Paso on Wednesday. Hide Caption 2 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Trump visits a joint operations center to meet with first responders of the El Paso shooting. Hide Caption 3 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Protesters in El Paso hold a sign written in Spanish that reads "Trump you are not welcome" during a rally held to denounce Trump's visit to El Paso. Hide Caption 4 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Democratic presidential candidate Beto O'Rourke, right, joins families in prayer during a visit to a makeshift memorial in El Paso. O'Rourke, a former congressman, is from El Paso. Hide Caption 5 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Trump supporters are escorted away by police after clashing with protesters outside the makeshift memorial in El Paso on Wednesday. Hide Caption 6 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Members of the Apache tribe stand alongside a priest during a vigil in El Paso. Hide Caption 7 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton A "Ban Assault Weapons Now" sign is displayed near a voter registration table in El Paso. Hide Caption 8 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton People pray Monday, August 5, at a makeshift memorial in El Paso. Hide Caption 9 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Doves are seen at El Paso's Horizon High School during a vigil for Javier Rodriguez, a 15-year-old who was killed in the El Paso shooting. Hide Caption 10 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Antonio Basbo holds the cross of his common-law wife, Margie Reckard, who died in the shooting in El Paso. Hide Caption 11 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton A woman kneels Monday at a memorial in Dayton. Hide Caption 12 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton People raise their arms in the air Sunday during a vigil for the El Paso victims. Hide Caption 13 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Mourners gather Sunday at a vigil in Dayton. Hide Caption 14 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Mourners pause for a prayer in Dayton. Hide Caption 15 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Flowers are placed in a bullet hole a few buildings away from where the shooting took place in Dayton. Hide Caption 16 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Mourners pray at a makeshift memorial for the victims of the El Paso shooting. Hide Caption 17 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Mourners gather at a vigil in Dayton. Hide Caption 18 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Doves are released during a memorial service recognizing the victims of the Dayton shooting. Hide Caption 19 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Mourners gather at Sunday's vigil in Dayton. Hide Caption 20 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton A butterfly grips onto Patricia Oliver during an El Paso vigil. Oliver's son, Joaquin, was killed in the Parkland, Florida, school shooting in 2018. Sunday would have been his 19th birthday. Hide Caption 21 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Someone holds up a sign during the vigil in Dayton. Hide Caption 22 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Children participate in an El Paso vigil Sunday. Hide Caption 23 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Edie Hallberg speaks to reporters near the site of the El Paso Walmart where people were killed Saturday. Hallberg's mother, Angie Englisbee, was killed in the shooting. Hide Caption 24 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton People pay their respects to the victims of the El Paso shooting at a makeshift memorial across from the Walmart near the Cielo Vista Mall. Hide Caption 25 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton A flag and letter signed by US Sen. John Cornyn is seen on flowers at a makeshift memorial in El Paso. Hide Caption 26 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton From left, Tiffany McConnell, Tanycia Leonard and Nikita Papillion recall their night in Dayton. Hide Caption 27 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Police conduct their investigation in the parking lot of an El Paso Walmart on Sunday. Hide Caption 28 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Evidence markers sit in a Dayton street on Sunday. Hide Caption 29 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Cristina Zapata and her children pay their respects to the victims of the El Paso shooting. Hide Caption 30 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton O'Rourke speaks to the media on Sunday. O'Rourke lashed out at President Trump during his comments, saying that Trump has been "promoting racism" with his incendiary remarks about immigration. After the El Paso shooting, Trump called the tragedy an "act of cowardice" and said there "are no reasons or excuses that will ever justify killing people." Hide Caption 31 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Shoes, hats and other items are piled together outside a bar in Dayton on Sunday. Hide Caption 32 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Witnesses comfort one another at the scene in Dayton on Sunday. Hide Caption 33 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Flowers left by mourners lie near the site of the shooting in El Paso. Hide Caption 34 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Bodies are removed from the scene of the mass shooting in Dayton. Hide Caption 35 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Authorities work at the scene in Dayton. Hide Caption 36 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton From left, Samuel Lerma, Arzetta Hodges and Desiree Quintanar attend a vigil in El Paso on Saturday. Hide Caption 37 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Walmart employees react Saturday after the shooting in El Paso. Hide Caption 38 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton A law enforcement officer stands outside the El Paso Walmart. Hide Caption 39 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Shoppers exit the El Paso Walmart with their hands up. Hide Caption 40 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton An El Paso police officer interviews a witness after the shooting. Hide Caption 41 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Kendall Long comforts Kianna Long, who was in the freezer section of the El Paso Walmart during the shooting. Hide Caption 42 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton People gather at MacArthur Elementary School in El Paso, looking for family and friends. The school was being used as a reunification center. Hide Caption 43 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton The El Paso shooting happened on a Saturday morning when the stores were busy with customers. Police said the first call about the shooting came in at 10:39 a.m., and police were on the scene within six minutes. Hide Caption 44 of 45 Photos: In photos: Deadly shootings in El Paso and Dayton Police speak to witnesses at a nearby Sam's Club in El Paso. Hide Caption 45 of 45

At least nine people were killed and at least 26 were injured in a popular nightclub district by a lone gunman, identified as 24-year-old Connor Betts. Dayton Police said the suspect is dead.

Last Sunday, a 19-year-old gunman wearing tactical gear opened fire at the Gilroy Garlic Festival in California , killing three people, including a 6-year-old boy and a 13-year-old girl.

And gunfire erupted Tuesday at another neighborhood Walmart in Mississippi, killing two employees and wounding a police officer. At least 34 people were left dead across all four scenes.

The National Rifle Association (NRA) released a statement on Twitter Sunday expressing condolences to the families affected by the shootings in Texas and Ohio and saluting first responders.

"The NRA is committed to the safe and lawful use of firearms by those exercising their Second Amendment freedoms. We will not participate in the politicizing of these tragedies but, as always, we will work in good faith to pursue real solutions that protect us all from people who commit these horrific acts," the statement read.

JUST WATCHED Video shows man hiding as shots ring out inside Walmart Replay More Videos ... MUST WATCH Video shows man hiding as shots ring out inside Walmart 00:50

The first call of an active shooter in El Paso went out at 10:39 a.m. local time, El Paso Police Chief Greg Allen said. The first officer arrived on scene at the Walmart near the Cielo Vista Mall six minutes later.

Adria Gonzalez was walking by the meat section on a Saturday morning shopping trip with her mom when she heard the shots.

She said she stepped up to see what was happening and that's when she saw the shooter near the main entrance, wearing headphones or earmuffs and carrying a gun.

"I could only think about getting my mom and others out of the store," she said. "We gotta get out of here."

After she saw the shooter, Gonzalez said she saw a grade-school aged boy get shot in the leg, a man bleeding on the floor and another man, covered in blood, reaching for a nearby child.

"We heard two to three shots, four to five shots, then six to seven shots," Gonzalez told CNN.

She and her mother took off -- along with about 40 other people, Gonzalez said. They waited in a storage area of the store until they no longer heard the gunfire.

"You see this happening in the movies, but when you live it yourself, when you see a person killing, the blood everywhere, you are in shock," she said.

'I never knew there was an odor to blood'

While authorities have not identified the victims, one was identified by her aunt as Jordan Anchondo

Anchondo was shopping for school supplies at Walmart when the shooting started, Elizabeth Terry told CNN. Anchondo was shot while using her body to protect her 2-month-old son from gunfire, Terry said.

The mother of three died alone at the hospital because the family didn't know where to find her, Terry said.

"How do parents go school shopping and then die shielding their baby from bullets?" she said.

Of the 20 killed, six were Mexican nationals, President Andrés Manuel López Obrador said. Of those injured, seven were Mexican, he said.

The shooting was "a terrorist act" against the Mexican community in the United States, Secretary of Foreign Affairs Marcelo Ebrard said Sunday at a press conference in Mexico City. He said his government was looking into the possibility of pursuing legal action.

The government will see whether there is enough evidence to solicit the extradition of the suspect to Mexico, he said.

Ebrard also identified the six Mexicans killed in the attack via Twitter Sunday. The victims were identified as: Sara Esther Regalado, Adolfo Cerros Hernández, Jorge Calvillo García, Elsa Mendoza de la Mora, Gloria Irma Márquez and María Eugenia Legarreta Rothe.

Officials from two local hospitals said they had received at least 24 of the victims. One of the 13 victims taken to University Medical center of El Paso died, spokesman Ryan Mielke told CNN Saturday. Eleven victims, ranging in age from 35 to 82, were taken to Del Sol Medical Center, Dr. Stephen Flaherty said.

"The ages and genders of all these people injured and killed are numerous in the age groups," Allen, the police chief, said Saturday. "The situation, needless to say, is a horrific one."

The next day, when asked why he used the word "horrific" to describe the scene, Allen told reporters, "There's not words you can place to say something like that. You have to see it for yourself."

"When I first got to this job," he said, "I never knew there was an odor to blood, but there is ... I can't tell you what it means ... It will leave an impression that you'll never forget."

Texas Gov. Greg Abbott called on flags to be flown half-staff from Saturday to Thursday.

'El Paso is just love'

El Pasoans showed up in force this weekend to demonstrate their determination to rise above the shooting.

Alfredo Angcayan, 62, a veteran who lives in Central El Paso came to leave flowers to the Walmart store. He says he had to support his community. pic.twitter.com/cWiaSmiR00 — Nicole Chavez (@NicoleChavz) August 4, 2019

A makeshift memorial began to grow Sunday outside the Walmart, where residents like 62-year-old Alfredo Angcayan dropped off bouquets of flowers. He told CNN he wanted to support his community.

Gabriel Gonzalez, 21, and his friends raised money Saturday night and went to another Walmart to buy as much water as they could. They filled up the bed of a pickup truck and spent Sunday driving around the city, handing the water out to law enforcement, residents, reporters and anyone else who needed it.

"We are not detectives," Gonzalez said. "We cant investigate the crime scene, but we can do this."

Anahi Holguín rode around with Gonzalez and another friend in the truck. She said she needed to help somehow.

"El Paso is just love," said Holguín, 21. "We can see somebody right here and say hi and we can start being friends in minutes, in seconds. That's why we're out here. We could be helping."

"It's a little bit, but we can help," she said.

Vigils were also held Sunday at Las Americas Headquarters and at Ponder Park, where the baseball field was filled entirely with people paying respects to the victims of the shooting.

At Las Americas, Democratic presidential candidate Beto O'Rourke, an El Paso native, called out President Donald Trumps rhetoric. He said the President traffics in hatred and incites violence by calling Mexican immigrants rapists and criminals and asylum seekers "animals and an infestation."

"You may call a cockroach an infestation. You may use that word in the Third Reich to describe those who are undesirable, who must be put down because they are sub-human. You do not expect to hear that in the United States of America in this age," O'Rourke said.