Investigators still have not found a motive for the Las Vegas shooting rampage that killed 58 people, Undersheriff Kevin McMahill has said.
The Clark County official said the authorities have looked at gunman Stephen Paddock’s personal life, political affiliation, economic situation and any potential radicalisation.
He said investigators are aware the Islamic State group has claimed responsibility for the attack, but so far there is no evidence that it had a role.
Mr McMahill said the authorities will continue to investigate those areas as well as look into leads and tips that come in.
Paddock unleashed gunfire on Sunday from the 32nd floor of the Mandalay Bay hotel casino on the Las Vegas Strip, killing 58 and injuring nearly 500 people.
He killed himself as police closed in.
The authorities are planning to put up billboards in Las Vegas to seek more tips as they investigate the deadliest mass shooting in modern US history.
Mr McMahill revealed at a news conference on Friday that police are confident there was not another gunman in Paddock’s room, and do not have any information that anyone else used his room key.
He said they are interested in Paddock’s medical history and are looking into that.
Paddock, 64, fired indiscriminately from his upper-level room at the Mandalay Bay hotel casino at people attending a country music festival below.