In the weeks before the Las Vegas shooting, the gunman attempted to purchase tracer rounds at a gun show in Phoenix.
Stephen Paddock, 64, did not use tracer bullets when firing into a crowd of more than 20,000 at the Route 91 Harvest Festival on Sunday night. However, law enforcement sources tell CNN that he was hoping to use the particular type of ammunition.
Tracer ammunition consists of bullets with a pyrotechnic charge that leaves an illuminated trace of its path after being fired.
Paddock was unable to obtain the tracer ammunition because the vendor at the Phoenix gun show did not have any to sell.
In the aftermath of the mass shooting, police have determined that 58 people were killed with more than 500 being injured. If Paddock had tracer rounds, authorities say that Paddock could have caused greater damage.
Art Roderick, a law enforcement analyst and former assistant director of the US Marshals Service, explained why Paddock would have wanted tracer rounds.
"It allows you to keep your weapon on not necessarily a specific target, but a specific area. ... There would have been a lot higher casualty rate if he had tracer rounds," Roderick said.
While Paddock would have been more accurate with tracer rounds, he also would have been tipping off the police as to his position, which was in his room on the 32nd floor of the Mandalay Bay Resort.
Because he didn't have tracer ammo, Paddock's location was difficult to determine from the outside.
"The barrel of the rifle -- we could not see muzzle flashes, from the angles I've seen on videos, which meant that he was ... pulled back inside," retired FBI supervisory special agent James Gagliano said.
In his hotel room, Paddock was in possession of 23 firearms. He also stockpiled weapons and ammo in his car, which indicated that Paddock was hoping to escape.
"He was doing everything possible to see how he could escape," Las Vegas Police Sheriff Joseph Lombardo said during a press conference on Thursday.
Former Las Vegas SWAT team member, John Sheahan, explained that Paddock would have likely been forced to cause further damage if he tried to escape.
"There's one of three ways it's going to end for an active shooter, and they pretty much all know this. You're either going to commit suicide; you're going to ... shoot it out with (police) and you're going to be killed; or you're going to continue on a preplanned rampage at locations b, c, d and e until the police finally stop you," Sheahan said.
"He rented the room in his own name. He's already on video coming in and out. We know who he is. He's going to be the most wanted man in the world if he does try to leave here," he continued.
As the investigation continues, more details are coming to light about Paddock's life before the shooting. Learn more here.