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Las Vegas Mass Shooter Grew Up in SoCal, Attended Schools in San Fernando Valley

Before Stephen Paddock opened fire from the 32nd floor of the Mandalay Bay hotel into a crowd of some 22,000 concertgoers in Las Vegas Sunday night, the man now responsible for the deadliest mass shooting in United States history grew up in Southern California and attended high school and college in the San Fernando Valley.

Stephen Paddock is seen in an image provided by CNN.

Stephen Paddock is seen in an image provided by CNN.

“He was kind of quiet, but I just remembered him being a nice guy,” said former California State Assembly Member Richard Alarcon, who attended John H. Francis Polytechnic High School with Paddock, and knew him since he was seven.

“He wasn’t a close friend of mine but we played on softball teams and football teams. Sometimes he would get picked with me and sometimes I would get picked with him,” Alarcon said Tuesday.

Paddock also attended and graduated from Cal State University Northridge, a spokeswoman said.

He completed a degree in business administration in 1977, Carmen Ramos Chandler wrote in a statement.

Paddock, 64 at the time of Sunday’s shooting, grew up to become a successful real estate investor who owned a number of apartments and houses, according to his brother Eric Paddock.

Stephen Paddock is seen in a photo provided by CNN.

Stephen Paddock is seen in a photo provided by CNN.

"There's absolutely no way I could conceive that my brother would shoot a bunch of people that he didn't know," Eric Paddock said Monday.

Eric Paddock described his brother as a poker-playing accountant with no apparent political or religious affiliation as far as he knew, CNN reported.

Former neighbors of Stephen Paddock didn't remember him ever talking about guns, but did notice his gambling.

"He was a gambler and a speculator, and he did that in Vegas," said Don Judy, who lived next door to Stephen Paddock from 2013-2015. Paddock once told Judy, "We're up all night because we gamble," CNN reported.

Married and divorced twice, Stephen Paddock most recently lived in Mesquite, Nevada, with his girlfriend Marilou Danley, who police said was out of the country during the shooting.

News that Paddock was the man responsible for killing 58 people and wounding more than 500 was shocking to Alarcon.

“If I had to pick somebody on that playground who might go crazy someday and kill a bunch of people it would never be him,” Alarcon said.

KTLA's Cindy Von Quednow contributed to this story.