The man who killed nine people early Sunday morningin a mass shooting on the streets of a popular nightlife area of Dayton, Ohio, has been identified.

The source says investigators have found writing about Betts, and that he “wrote about killing people.”

“We believe he was planning this or something like this for a while,” the source says.

His motive remains a mystery. According to the source, his writings showed “no political themes, no racial themes.”

The source adds that “what we found supports the theory that the Dayton shooter was not connected to the El Paso shooter. If there’s a connection, it may be only in terms of spurring the other to act on a plan that was in the works. These do not appear to be coordinated attacks.”

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Dayton shooting

At a press conference, Dayton Mayor Nan Whaley said the shooter was wearing body armor and carrying a .223-caliber rifle while also carrying high-capacity magazines.

Dayton, Ohio shooting

Whaley said that if not for the quick police response, “hundreds of people in the Oregon District could be dead today,”reports the Associated Press.

Assistant Chief of Police Matt Carper said at the press conference that the shooter began firing at 1:07 a.m. and that there was a “very short timeline of violence” before the attacker was killed,USA Todayreports.

The Dayton shooting followeda mass shooting in El Paso, Texas, inside a Walmartin which 20 people were killed and 26 were injured.

Police arrested a 21-year-old male suspect in El Paso and authorities are investigating the shooting as a hate crime after learning the suspect apparently wrote a manifesto with white nationalist themes, a source familiar with the investigation tells PEOPLE.

NBC News, citing eyewitnesses, reports the Dayton shooting took place near the Ned Peppers bar.

In a Facebook post, the bar said, “We have police regularly staffed next to our business who engaged the shooter and neutralized the threat.”

source: people.com