At least 19 people have been killed in El Paso, Texas after a gunman armed with an AK-47 entered a shopping and began firing.

The gunman has been identified as 21-year-old Patrick Crusius. He has been taken into custody by law enforcement.

Investigators are looking into a manifesto allegedly posted online by Crusius days before the shooting. According to sources, the manifesto voiced anti-Hispanic sentiments and decried the immigrant “invasion” of El Paso.

Additionally, a Twitter account that likely belongs to the gunman has emerged. The account was created in 2016 and the last sign of activity on the account was in 2017. However, it shows more than one post that voiced support for President Trump.

In one post from January 2017, the user believed to be Crusius shared a survey which asked, “What is the best way to secure our country?”

Other posts on Crusius’ alleged Twitter account shows an apparent hostility towards animal rights activists. In one reply to the “Mercy for Animals” official account, the user writes, “Ugh you hipsters don’t realize that it is God’s will for humans to do whatever they please with animals. Foolish people say otherwise!!!”

Initial reports said “multiple” suspects were taken into custody in the wake of the shooting, but police are now confirming that the possibility of more than one suspect has been “ruled out.”