The elder Paddock, whose nicknames included "Big Daddy" and "Chrome Dome", was charged in 1960 with stealing about $25,000 from three separate bank branches in Phoenix, Arizona.
Armed with what appeared to be at least one automatic weapon, Stephen used the elevated vantage point to fire into the crowds across the Las Vegas Strip at the Route 91 Harvest festival, where the country singer Jason Aldean was onstage.
The gunman was found dead by Las Vegas SWAT officers in his hotel room at the Mandalay Bay Resort and Casino.
News that Paddock was the man responsible for killing 59 people and wounding more than 500 was shocking to Alarcon.
The brother of Paddock, Eric, told Orlando Sentinel he was "dumbfounded", saying: "We are completely dumbfounded".
But the younger Paddock himself had never been in any serious trouble.
Paddock is thought to have brought 10 suitcases into the hotel room he had been staying in since Thursday, with no questions asked by housekeepers who serviced the room.More news: Netflix commits $500m to Canada location filming
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Mesquite, Nevada, police spokesman Quinn Averett, said: "What's unique for us is the gunman, the shooter, and the person with him, we in the Mesquite Police Department have not had any contact with these people in the past".
He described his brother as a multimillionaire and said they had business dealings and owned property together.
He died by his own hand inside that Vegas hotel room. Prior to that, he is said to have been an auditor, The Telegraph reports. Special Agent in Charge Aaron Rouse said at a news conference Monday that the shooter had no connection to an worldwide terrorist group.
Eric Paddock recalled receiving a recent text from his brother showing "a picture that he won $40,000 on a slot machine".
Former neighbors of Stephen Paddock didn't remember him ever talking about guns, but did notice his gambling. Independent Journal Review reports that he lived with one other person, Marilou Danley, an Australian citizen who is now a person of interest.
The suspect had a pilot's license but he was not up to date on his medical certification which he would need in order to fly legally, a federal official said.
The FAA will not release any information regarding his mental health from his last certification in 2008 because it is protected under federal privacy rules.