Police have chased down more than 1,000 leads, but they still don't know why the Las Vegas shooter carried out his massacre

Las vegas police undersheriff kevin mcmahillYouTube/The Washington PostUndersheriff Kevin McMahill

Las Vegas authorities on Friday said that after running down “well more than 1,000 leads,” they remain clueless as to why 64-year-old Stephen Paddock decided to open fire on a crowd of concertgoers on Sunday, killing 58 people in the deadliest mass shooting in modern US history.

Undersheriff Kevin McMahill of the Las Vegas Metropolitan Police Department said at a press briefing the department has been exploring every aspect of Paddock’s life, from birth to death, in search of an explanation. He said they have looked into details regarding Paddock’s personal life, political affiliations, social behaviours, economic situation, even possible radicalization — but answers remain evasive.

“We have been down each and every single one of these paths trying to determine why. Trying to determine who else may have known of these plans,” McMahill said, adding that the rumours and speculation that have abounded in the wake of the shooting have been unhelpful to their investigation.

“In the past, terror attacks or mass-murder incidents, motive was made very clear, very clear in most of those cases by a note that was left, by a social media post, by a telephone call that was made, by investigators mining computer data,” McMahill said. “Today in our investigation, we don’t have any of that uncovered. I wish we did. We will and are continuing to investigate with great tenacity and hope to arrive at an answer.”

McMahill also shot down several prevalent rumours that have circulated throughout media reports, telling reporters that they are confident no second shooter was in the room with Paddock during the attack. He said he could not, however, confirm whether any other people knew about Paddock’s plans to carry out the shooting.

McMahill also said investigators do not believe anyone other than Paddock accessed his suite before the attack, despite reports suggesting a room key was used to enter his suite while Paddock’s car was outside the hotel’s parking garage.

He also said the Tannerite — an explosive powder used for long-range target practice — that was recovered from Paddock’s home was not in a condition to be used in an IED, as others had questioned. McMahill said it was also unclear what Paddock intended to do with the tannerite.

Investigators are, however, “keenly interested” in Paddock’s medical status at the time of the shooting, McMahill said. The Las Vegas Review-Journal recently reported that Paddock had been prescribed the anti-anxiety drug diazepam — also known by its brand name, Valium.

But authorities said the continued lack of an apparent motive has prompted them to turn to the public for help. Local police, in conjunction with the FBI, are planning to set up billboards around the city saying, “If you know something, say something,” along with the number 1-800-225-5324 (or 1-800-CALL-FBI) for tips.

“It’s really imperative that the listening public have a very clear understanding that there are still a number of people out there that know that something looked out of place,” McMahill said. “Someone may have been acting suspiciously that night, or in the years prior, the months prior. Somebody that may have seen something or know something.”

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