Morning briefing: What drove the Las Vegas killer?

Why? What could possibly have motivated Stephen Paddock, a retired accountant, to open fire from a balcony above a Las Vegas music festival, killing at least 59 people and injuring more than 500? Police found 23 guns in Paddock's hotel room, but have not discovered any connection to international terrorism, despite a claim of involvement from so-called Islamic State. President Donald Trump described the act as "pure evil" and some investigators say there is reason to believe the gunman, 64, had a history of psychological problems. Meanwhile, searches have uncovered explosives at Paddock's home in a retirement community in the small town of Mesquite, north east of Las Vegas. There is a second house in northern Nevada which Swat teams are due to check for booby-traps before carrying out a search. The authorities have yet to confirm the identities of any of the people killed, but Jordan McIldoon, 23, from British Columbia in Canada, has been named as a victim of the attack by CBC News.