"There was maybe a total of 13 kids running around but I can only get three, and I think he got about three as well", he said. The manifesto, reportedly, spoke about the "invasion" of Latino immigrants in the state.
Three people were killed, including two children.
Various news reports said the ages of victims being treated at hospitals ranged from two to 82 years. They were not hurt, Quezada said.
Police spokesperson Robert Gomez said authorities had ruled out the possibility of multiple shooters.
There were reports of gunfire in several locations - in both the Cielo Vista mall and the nearby Walmart, police said - but reports of further gunshots at another nearby mall, Bassett, were not true.
Speaking to reporters outside a hospital where he was visiting victims of the shooting, O'Rourke said Trump had proven himself a racist with his recent attacks on four ethnic minority congresswomen and his past branding of Mexicans as rapists.
The suspect surrendered to police as officers closed in on him, and he was taken into custody without incident, according to authorities.
Beto O'Rourke, a former USA congressman for El Paso who is now running for president, cut off his campaigning in the wake of the shooting.
This is at least the 249th mass shooting in the US this year, according to the Gun Violence Archive.
He said he heard early reports that the shooter might have had a military-style weapon, saying we need to "keep that (expletive) on the battlefield. Do not bring it into our communities". El Paso is almost a 10-hour drive from Allen. "And it does not just offend our sensibilities, it fundamentally changes the character of this country and it leads to violence", said O'Rourke, who represented El Paso in the US Congress until recently.
Stores at the mall were also locked down as police officers cleared the shopping center in the east of the city, which lies on the southern USA border with Mexico.
O'Rourke stressed that border walls haven't made his hometown safer.
Citing a law enforcement source, El Paso television station KTSM published on its website what it said were two photos of the suspect taken by security cameras as he entered the Walmart.
The city averaged 18 murders a year over the past five years and has a significantly lower violent crime rate than similar-sized USA cities.
The carnage ranked as the eighth-deadliest mass shooting in modern USA history, after a 1984 shooting in San Ysidro, California, that claimed 21 lives.
"There are no reasons or excuses that will ever justify killing innocent people". Before Saturday, 96 people had died in mass killings in 2019 - 26 of them in public mass shootings. Since 2006, 11 mass shootings - not including Saturday's - have been committed by men who are 21 or younger.