The man accused of killing 22 people at a shopping center in El Paso, Texas, last Saturday said he deliberately targeted "Mexicans" during the assault, according to police documents.
The records provided additional details regarding the arrest of the suspected shooter, 21-year-old Patrick Crusius.
According to an affidavit, Crusius emerged from his vehicle with his hands up after he was stopped at an intersection shortly after the attack, telling police, "I'm the shooter." He then told detectives he entered the Walmart store with an AK-47 assault rifle and several magazines, and that he was targeting "Mexicans."
Of the 22 people killed in the attack, eight were Mexican nationals. Nearly all the victims were of Hispanic origin.
Crusius is believed to have posted a racist screed online shortly before the attack, in which he railed against a "Hispanic invasion" of the United States. He claimed to be "defending" the United States "from cultural and ethnic replacement" and referenced the Christchurch shootings in New Zealand, where a white supremacist killed 51 people at two mosques in March.
Investigators say Crusius drove over 10 hours from his hometown near Dallas to carry out the shooting in the border city of El Paso, which is overwhelmingly Hispanic. He has been charged with murder and is being held without bond. Federal prosecutors have said they are also considering charging Crusius with hate crimes.
The shooting in El Paso came just hours before another attack in Dayton, Ohio, which left nine people dead.
The attacks have inflamed tensions over race and gun control in the US. Many Americans blame President Donald Trump for fueling hostility toward immigrants and minorities with his rhetoric. Trump has also been criticized for resisting tougher gun control measures.
On Friday, Trump said he hoped to rally Republicans around stronger federal background check laws. Republican Senate Majority Leader Mitch McConnell signaled the Senate could potentially look at a ban on assault weapons, telling a radio station it was a "front and center" issue.