The man suspected of killing 20 people and injuring 26 others in El Paso on Saturday may face hate crime and capital murder charges, officials said.
Police say a document they believe was written by the 21-year-old white male suspect has a "nexus to a potential hate crime."
The four-page document posted online espouses white nationalist and racist views. It rails against immigrants and Hispanics, blaming immigrants and first-generation Americans for taking away jobs and for the blending of cultures in the US.
"Right now, we have a manifesto from this individual that indicates to some degree he has a nexus to a potential hate crime," El Paso Police Chief Greg Allen said at a press conference.
FBI El Paso Special Agent in Charge Emmerson Buie said more investigation is needed before determining that the mass shooting was a hate crime.
"Right now, it is a murder investigation," Buie said. "There is potential for a number of different other violations, and we're reviewing all the evidence to make a determination as to what potentially else is out there, in addition to the violations that have been stated that the local authorities are pursuing."
The suspect has been identified as Patrick Crusius of Allen, just outside Dallas, three sources told CNN. Two federal law enforcement sources and one state government source confirmed the suspect's identity.
The suspect surrendered to police "without incident," police spokesman Sgt. Robert Gomez told reporters.
The document police believe the suspect wrote was posted on 8chan, an online messaging board full of racist, bigoted and anti-Semitic content. A CNN analysis of the document reveals it was posted less than 20 minutes before police received the first calls about the shootings.
"This is disgusting, intolerable. It's not Texan," Abbott told reporters who asked about the document. "We are going to aggressively prosecute it both as capital murder, but also as a hate crime, which is what it appears to be, without having seen all the evidence yet."
The FBI has opened a domestic terrorism investigation, to be worked concurrently to the state investigation into the shooting, with Texas authorities taking the lead, a source familiar with the investigative process told CNN.
The FBI, the source indicated, is bringing resources from neighboring satellite offices and assets are on standby to assist should the state request.
President Donald Trump called the mass shooting an "act of cowardice," and said there "are no reasons or excuses that will ever justify killing people."
In his messages on Twitter, Trump said he and the first lady sent "heartfelt thoughts and prayers to the great people of Texas."