Barker has supervised multi-agency law enforcement investigations in the past and conducted an analysis of Omar Mateen, the gunman who killed 49 people and wounded 58 others at the Pulse Nightclub in Orlando.
Like Orlando, Barker said agents and officers in the Las Vegas investigation will work around the clock filing applications for search warrants for Paddock's records, retrace his steps as far and wide as possible and conduct interviews that, in some cases, could last several days.
During a news conference that ended within the last hour, the FBI confirmed the swarming.
The FBI has deployed more than 100 personnel from across the nation to assist the Las Vegas division in this investigation, including victim-witness assistance, EAP counselors, evidence techs and technical assets.
"We don't want the whole family there. We don't want friends and spouses there. We want to have an individual by themselves," Barker said.
Perhaps the most critical interviews will be with Marilou Danley, Paddock's former girlfriend, who left the country.