Vegas Police Hunt for Gunman's Motive

We hear from Republican State Senator Don Gustavson, a member of the Nevada legislature opposed to tightening gun laws.

Also on the programme: Large crowds gather in Catalonia to protest against Spanish police tactics during Sunday's disputed independence referendum; and one of the physicists who has won this year's Nobel Prize for the discovery of gravitational waves.

(Photo: Mourners attend a candlelight vigil for the victims of Sunday night's mass shooting in Las Vegas. Credit: Getty)