1,000 leads later, authorities still stumped by Vegas gunman

More than a week after the deadliest mass shooting in modern U.S. history, investigators are still stumped about what led a high-stakes gambler to kill 58 people and wound hundreds of others at a country music concert.

It's an answer they may never find.

The FBI and Las Vegas police have sorted through more than a thousand leads and examined Stephen Paddock's politics, finances and social behavior. But the typical investigative avenues that have previously helped uncover motives in past shootings have yielded few clues.

Clint Van Zandt, a former FBI profiler and hostage negotiator, says in not leaving behind an easily accessible manifesto, Paddock defied societal expectations that mass murderers will want their disturbed motives known to the world.