Mass shootings kill 29 in Texas, Ohio over weekend

It was the deadliest shooting in the US this year. The number of people killed would make it one of the 10 worst in recent US history.

A 2,300-word "manifesto", which investigators were working to confirm was posted by Crusius, declares support for the gunman who killed 51 people in Christchurch, New Zealand, outlines fears about Hispanic people gaining power in the US and appears to discuss specific details about elements of the attack, including weapons, according to a New York Times report.

The manifesto "indicates to some degree a nexus to a potential hate crime", El Paso Police Chief Greg Allen told reporters. But the FBI said it needs further investigation to determine whether it would be classified as a hate crime or an act of domestic terrorism - both federal crimes.