Police say that they found child pornography on his computer.
No one knew of his whereabouts after he was evicted from the shop in 2014, but police have been looking for him since.
TMZ sources also say that the investigation into Bruce began before the shooting at the Vegas music festival happened earlier this month.
The FBI and Los Angeles Police Department used a joint task force to carry out the arrest.
The child porn case predated the October 1 shooting, authorities said. The investigation was launched after evidence was discovered at a business in the city's Sun Valley neighborhood.
Bruce Paddock, 59, was arrested on a 20-count felony complaint, a police statement said.
Over the years, he has faced charged of arson, criminal threats and burglary, according to court documents obtained by TMZ.
Investigators digging into Paddock's background also learned he purchased software created to erase files from a hard drive, but without the hard drive to examine it is impossible to know if he ever used the software, one source said.
Paddock committed the deadliest mass shooting in modern USA history Sunday night when he shot into a crowd killing 49 people and wounding over 500.