Police found a note in the hotel room of Stephen Paddock, the gunman behind the mass shooting in Las Vegas, that had hand-written calculations about where he needed to aim to kill as many people as possible.

In an interview that will be aired Sunday on CBS's "60 Minutes," Officer Dave Newton from the Las Vegas Police Department's K-9 unit said he noticed a note on the shooter's bedside table after officers entered the room. The note was next to one of the windows that Paddock smashed with a hammer to clear an opening to fire into the crowd from his 32nd-floor hotel suite at the Mandalay Bay Resort and Casino.

"I could see on it he had written the distance, the elevation he was on, the drop of what his bullet was gonna be for for the crowd," Newton said. "So he had had that written down and figured out so he would know where to shoot to hit his targets from there."

Using semi-automatic rifles that he modified with a "bump stop" to increase their rate of fire, Paddock on Oct. 1 killed 58 people and injured nearly 500 others. Paddock, 64, killed himself with a gun before police entered the room to find his body and 47 weapons.

More than 20,000 people were attending the Route 91 Harvest Music Festival when Paddock began shooting into the crowd, which was about 400 yards away.

Police used an explosive to blow through the door of Paddock's room, which set off flashing lights and a fire alarm.

"Very eerie. Yeah, the dust from the explosive breach. And then you have the flashing lights," Newton said. "And that looked straight, like, out of a movie, you know?"

Police have still not determined the motive for the attack and said they aren't yet sure whether anyone else was involved.

On Friday the family of John Phippen, 56, a man who was killed in the attack, petitioned a court to freeze Paddock's assets and for the county's public administrator to take possession of them. This would prohibit Marilou Danley, Paddock's longtime girlfriend, and any of his siblings or other family members from transferring his money.

The petition was filed in the Clark County District Court and asks the judge to appoint Clark County public administrator John Cahill to oversee Paddock's estate so the Phippens and others who "suffered loss, distress and injuries" can pursue lawsuits against the estate, according to ABC News.