>> One week after the deadliest mass shooting in modern US history, and investigators still don't have a clear reason why Steven Paddock fired on a music festival crowd of 22,000 people. In a 60 minutes interview, the officers who first approached Paddock's Mandalay Bay hotel room said he screwed shut a stairwell door to slow them down.
And said once inside the room, they were tripping over guns and ammo. Police saying Paddock left behind no suicide note, no manifesto, no recordings, and no messages on social media pointing to his intent. The flashing marquee lights on the Las Vegas strip dimming Sunday night to honor the 58 dead and roughly 500 injured.
A vigil was also held near the site of the massacre. The FBI has begun returning the thousands of purses, phones and other personal property left behind by concert goers, a process that could take weeks. Authorities began returning vehicles left in the concert grounds to their owners last week, forcing many to relive the nightmare.
>> It's really hard to describe. It's like a war zone, obviously.