The Texas man accused of killing 22 people at a Walmart in El Paso, in an attack that authorities said targeted people of Mexican descent, pleaded not guilty in court Thursday.

Patrick Crusius, 21, entered the plea during a brief court appearance.

Court documents previously released say that he confessed to opening fire at the store on Aug. 3, that he told police "I'm the shooter" when he surrendered and that in an interview with detectives he "stated his target were 'Mexicans.'"

Crusius is charged with capital murder and is being held without bail.

In his brief appearance, Crusius, wearing a navy suit and white shirt, told the judge he was the defendant, looked over the indictment and indicated his full name was correct in the indictment. He waived the reading of the document and entered the plea of not guilty.

A law firm representing Crusius' family later released a statement on their behalf in which the relatives said they were aware of the not guilty plea, NBC affiliate KTSM of El Paso reported.

"Again, we continue to pray for the victims and everyone involved, including all those now tasked with their roles in the process of our judicial system,” the family statement said in the statement.

Prosecutors have said they will seek the death penalty. Federal authorities are also weighing capital murder and hate crime charges. A federal prosecutor has said federal officials are treating the case as domestic terrorism.

Just before the attack, which authorities have said was carried out using an AK-style rifle, a hate-filled racist screed linked to the suspect was posted on 8chan, an online forum popular with extremists.

The rant decried the "invasion" of Mexican immigrants to the United States and hailed the Christchurch, New Zealand, mosque shooter, an anti-immigrant white supremacist who left 51 dead in March. The writer said he was angry about Mexican immigration long before the election of President Donald Trump, who based much of his 2016 campaign on building a wall between the U.S. and Mexico.

An overwhelming majority of those killed in the store had Spanish surnames. El Paso's population is more than 80 percent Hispanic, according to census data. Eight Mexican citizens were among those killed. One of the dead was a German citizen who lived in Ciudad Juarez, Mexico.

Documents filed Thursday say prosecutors have turned over evidence with defense attorneys, including an FBI "manifesto analysis," the Associated Press reported.

The Crusius legal team appealed for open minds as they present their portrait of Crusius, according to the news service.

"There are two sides to this story," said Mark Stevens of San Antonio, lead defense attorney. "We'll ask everybody, media and everybody else, to keep an open mind until you hear both sides of the story, what comes out in the courtroom."

Another of his defense attorneys, Joe Spencer, said that he and Stevens are morally opposed to the death penalty and will do everything they can to spare Crusius' life, according to the AP.