Bruce Paddock, 59, was arrested last month in North Hollywood, California, at an assisted living home by a joint task force that included the FBI and the LAPD.
Law enforcement sources told TMZ that the day after Stephen Paddock opened fire at a Las Vegas country music festival, his brother began bragging to other patients at the facility about what his brother had done.
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After a staff member at the home checked Bruce's file and discovered Stephen Paddock was listed as his emergency contact, the employee alerted the Los Angeles Police Department, assuming officials would want to interview him in connection with the shooting.
When the FBI began investigating Bruce Paddock, an active search warrant in a 2014 child porn case was discovered, according to TMZ.
The damning evidence was allegedly first discovered over two years ago when Bruce Paddock was evicted from a business in Los Angeles, where he was a squatter.
Paddock was homeless at the time and remained on the lam until police were tipped off that he was living at the North Hollywood facility.
He is facing one felony count of possession of child or youth pornography and 19 counts of sexual exploitation of a child.
Last month, it was revealed that Paddock's father, Patrick Benjamin Paddock, was a bank robber who used to be on the FBI's Most Wanted list.
He was known as "Chrome Dome" for his shaved head and was captured in 1978 while running a bingo parlor in Oregon.
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- This article was initially published on AOL.com: Report: Bruce Paddock's brags about being related to Las Vegas shooter led to his child porn arrest