This undated file image provided by the Federal Bureau of Investigation shows Patrick Crusius, whom authorities have identified as the gunman who killed multiple people at an El Paso, Texas, shopping area.
Democratic presidential candidate Beto O'Rouke on Saturday joined a march in the Texas border city of El Paso to condemn last week's mass shooting there, telling the crowd that President Donald Trump was partly responsible for the hatred that inspired it.
The affidavit, drawn up by El Paso police detective Adrian Garcia, said that Crusius, 21, waived the right to an attorney and agreed to talk to the officers.
Investigators are trying to confirm whether Crusius was the also author of a statement posted online roughly 20 minutes prior to the shooting that called for halting an "Hispanic invasion" of Texas.
Crusius has been charged with capital murder in the shooting and is being held without bond.
State prosecutors in El Paso announced on Sunday that they will pursue the death penalty.
The records provided additional details regarding the arrest of the shooter, 21-year-old Patrick Crusius.
Dallas attorneys Chris Ayres and R. Jack Ayres told CNN that she called to the Allen Police Department to ask about an "AK" type firearm Crusius owned. Mexican officials say eight Mexican nationals were among 22 people killed in last weekend's attack at a Walmart. The lawyer added that Crusius did not identify herself or her son to police when she made the call and that the department did not file the call or follow up on it.
Including the two latest attacks, 126 people had been killed in the 2019 mass shootings.
During the Gilroy shooting, six days before the El Paso attack, a gunman killed three people before fatally shooting himself.
Trump said that there is no justification for the killing of innocent people.
El Paso is located along the border with Mexico, and has a large Hispanic population.
The shootings in Texas and OH were the 21st and 22nd mass killings of 2019 in the USA, according to the AP/USA Today/Northeastern University mass murder database that tracks homicides where four or more people killed - not including the offender.
Sunland Park Racetrack & Casino is donating $100,000 to be distributed between the El Paso Community Foundation's El Paso Shooting Victims' Fund and the Paso del Norte Community Foundation's El Paso Victims Relief Fund.
It is not clear if the weapon used in the attack was the same one the suspect's mother contacted police about.