The FBI has beefed up security in Reno, Nevada, after a group of burglars broke into the heavily guarded home of Las Vegas mass shooter, Stephen Paddock over the weekend.

According to authorities, a number of unidentified individuals descended on Paddock's home in the Del Webb retirement community just outside Reno, bypassing both state and federal law enforcement who were assigned to protect the property.

Local law enforcement says it's not clear how the group got into the home, which is supposed to be under round-the-clock surveillance, and they do not have any suspects — but they also believe nothing was taken from inside the home, as the home was left completely undamaged.

The break-in prompted FBI officials to undertake a second search of the home, but they didn't say why — just that they needed to "revisit" the suspect's home in light of other evidence.

"Is the FBI along with LVMPD revisiting the personal property of the suspect? Yes, that is accurate along with the behavioral analysis detectives,” an FBI spokesperson told media Wednesday. “They are also present and maybe we can discern additional evidence as a result of that revisit.”

On the first go-round, authorities found a second cache of weapons — in addition to the ones Paddock had used to outfit his snipers nest on the Mandalay Bay Hotel And Casino's 32nd floor. They recovered at least ten guns (two shotguns and the rest handguns), a "pile of ammunition" and several unspecificed "electronic devices" which might have been related to Paddock's plan to build explosives.

Residue from several chemicals used to make home-made bombs was found inside the home, the hotel room, and Paddock's car.

The shooting investigation has now entered its second week, but authorities say they still have no idea what motivated Paddock to cart hundreds of pounds of artillery up to his Vegas hotel room, blow out two 32nd floor windows, and rain bullets down onto a country music festival below, killing 58 and wounding several hundred more.

Paddock's autopsy yielded no clues — his brain showed no abnormal function — and Las Vegas Police Department and Mandalay Bay are trying to, between them, hash out a shooting timeline. On Wednesday, a Mandalay Bay maintenance man revealed that he'd reported the shooter to hotel authorities, and instructed them to call the police,