The US probing agencies have speeded up their investigation soon after Islamic State claimed Stephen Paddock to be a member of the international radical terrorist group.
Paddock unleashed a barrage of gunfire on an outdoor Route 91 Festival across the street, killing more than 50 people and wounding at least 400 others.
The security officers who broke into the hotel room from where Paddock opened fire at the concert have recovered 10 rifles and several documents.
Sheriff Joseph Lombardo talking to reporters said, “We have recovered rifles and several documents.”
An FAA spokeswoman Laura Brown told the media that Paddock had a private pilot's license and the FAA is gathering his records.
Investigative officers on examining the recovered documents have learnt that the Las Vegas killer was staying in Mesquite, a town on Las Vegas Strip state line 82 miles northeast of Las Vegas.
The probing team is trying to find out since how long he has been staying in the address.
Sleuths of different agencies probing the killing have learnt that Paddock was staying in 32nd floor of Mandalay Bay Resort and Casino in Las Vegas since Thursday.
Agencies have found no derogatory information or crimincal record about Paddock.
Islamic State a few hours after the incident has claimed that Paddock has recently adopted Islam recently.