Las Vegas shooting: Paddock may have planned to escape

The gunman behind Sunday night's mass shooting in Las Vegas planned to flee, and he may have had help with planning the massacre, officials suspect.

Stephen Paddock was "living a secret life, much of which would never be fully understood", Sheriff Joe Lombardo told reporters.

The gunman's girlfriend said she had no idea what he was plotting.

Paddock's motive for killing 58 people in the largest mass shooting in modern US history remains unclear.

Police found the 64-year-old former accountant dead in a room on the 32nd floor of a hotel after he sprayed bullets on concert-goers below, injuring hundreds.

He apparently turned one of his many guns on himself as police closed in.