On Oct. 1 at country music concert in Las Vegas, Nevada, 64 year old Stephen Paddock rained bullets into the crowd from an overlooking hotel room. Paddock killed at least 59 people and injured over 400 in this mass shooting. Oddly enough, Paddock has never had any run ins with the law and there are no ties linking him to a terrorist group.

Paddock was an accountant with a penchant for high stakes gambling. He was the son of a notorious bank robber and his own crime demonstrated some amount of sophisticated planning.

What brought Paddock to the 32 floor of the Mandalay Resort and

Casino and fire upon the unexpecting crowd is still unknown to the police.

“I can’t get into the mind of a psychopath,” Joseph Lombardo,the sheriff of the Las Vegas Metropolitan Police Department, said to a CNN reporter.

Police say Paddock stayed in the suite for many days with an arsenal of 23 guns ranging from all different calibers.  One of the guns he used in the attack was an AK-47 type rifle, with a stand to hold it steady as he fired upon the concertgoers. One of the many questions police are asking themselves is how Paddock came to carrying the automatic weapon and how he got into the hotel without being suspected.

Lombardo said hotel staff had been in and out of the two-room suite, which Paddock had stayed in since Sept. 28, and spotted nothing nefarious, even though he had more than 10 suitcases.

Investigators on the case believe at least one of the guns functioned as if it were fully automatic, and they are now trying to determine if he modified it or other weapons to be capable of shooting constantly by holding down the trigger.

Gun purchase records indicate Paddock legally acquired more than 24 firearms across a period of years. Guns & Guitars, a store in Mesquite, Nevada, said in a statement to CNN, that Paddock purchased some of his weapons there, but employees followed all required steps stated by the law and Paddock never gave a sign of being unstable.

The amount of deaths in Las Vegas was massive, overtaking the 49 people killed by a gunman in Orlando in June 2016. That shooter, who later said he was inspired by the Islamic State, opened fire inside a crowded nightclub. And Lombardo said in a statement to CNN, the number of dead from Sunday’s concert shooting could rise, as an additional 527 were thought to have been injured.