Paddock was taken into custody on Wednesday, as part of a joint investigation involving the Los Angeles Police Department and the Federal Bureau of Investigation, an FBI official tells PEOPLE. Authorities declined to say more about the situation, but a law enforcement source told the Associated Press that the child pornography investigation occurred prior to the shooting in Las Vegas.
This is a developing story.
Bruce Paddock had a lengthy criminal history well before his brother opened fire on concertgoers along the Las Vegas Strip on October 1.
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"They were just asking about our childhood, what schools we went to, who his friends were", Paddock said. A criminal complaint filed by prosecutors in Los Angeles County lists 19 counts of sexual exploitation of a child and one count of possession of child pornography.
The report also said Paddock may have removed the hard drive before killing himself. Stephen Paddock opened fire from the Mandalay Bay casino-hotel tower.
At the time, Bruce Paddock was a transient and couldn't be found, police said.
Almost a month after the shooting, authorities are still attempting to determine the motive behind the shooting, the deadliest in modern USA history.