Authorities say they still don't have a clear motive for the Las Vegas shooting rampage.

Undersheriff Kevin C. McMahill provided an update on the investigation Friday. He says authorities have looked at gunman Stephen Paddock's personal life, political affiliation, economic situation and any potential radicalization.

He added that Jesus Campos, the security guard who first confronted the Las Vegas attacker during the attack, is a true hero.

He says authorities are aware the Islamic State group has claimed responsibility for the attack, but so far there is no evidence that it had a role.

He says authorities will continue to investigate those areas as well as look into leads and tips that come in.

Paddock unleashed gunfire Sunday from the 32nd floor of the Mandalay Bay hotel casino on the Las Vegas Strip, killing dozens and injuring hundreds of people. He killed himself as police closed in.