LAS VEGAS (NewsNation Now) — A terrorism investigation led to the arrest last September of a Las Vegas man now jailed in what police called an apparent plot to mount a mass casualty attack, authorities said.

Police arrested Lacy Walthour, 27, in September 2020, but details of what police call a terror plot were not widely released until a ceremony to commend the investigators involved last week.

On Sept. 22, 2020, Walthour called 911 to report a person attempting to burglarize cars in his driveway. The call lasted only a few seconds and Walthour hung up.

A few minutes later, Walthour called 911 again, saying he had fired his gun at the suspect who ran out of the area.

A video shown to a grand jury shows Walthour standing in the driveway and aiming his gun at a person walking on the other side of the road.

“Neighborhood Watch! Neighborhood Watch!” Walthour screams to the man seconds before he fires his gun, investigators said.

“We’re going to send someone over there to talk to you. Make sure the gun is put away now, OK? A dispatcher later told Walthour in the second 911 call.

“Do they need to see it? Should I give it to them?” Walthour responded.

“No. Just for now, just keep it put away. But we’ll send someone over to contact you,” the dispatcher said. “They’re already in the area looking around, OK?”

Officers obtained a search warrant and reported finding a hand-painted portrait of Osama bin Laden, gun parts, a 3D printer, components for explosive devices, body armor and a computer in Walthour’s home, and homemade step-on explosive devices in the garage.

Detectives entered the home to search for anyone injured and to find the gun involved, they wrote in Walthour’s arrest report.

Inside, they found weapons and other materials they said could be used “in carrying out an ideologically motivated mass casualty attack.”

A painting of bin Laden hung on the wall. The artwork included the phrase, “One man’s terrorist is another man’s freedom fighter,” which was written in Arabic, police said.

Investigators also found a 3D print they said was used to make gun parts and various components for incendiary explosive devices. An investigator wrote the IED components resembled “what foreign terrorist organizations used to target and kill U.S. and allied military personnel.”

They said that counter-terrorism detectives also found a composition notebook filled with recipes to make bombs and other homemade devices.

On one page, investigators said Walthour wrote about “government unrest” and chemicals that would irritate people’s eyes.

Other pages include scientific formulas, directions to make different kinds of bombs, and a list of poisonous plants.

Court records indicate Walthour was searching for a new lawyer. The state offered Walthour of plea deal of 15 years in prison, which he declined.

The NewsNation affiliate KLAS filed a request to speak with Walthour from jail. He agreed only if KLAS paid him $5,000.

Walthour faces the following charges:

• Attempted murder with the use of a deadly weapon
• Discharging a firearm at or into an occupied structure (7 counts)
• Discharging a firearm at or into an occupied vehicle
• Manufacturing and/or possessing an explosive or incendiary device
• Possession of an explosive or incendiary device in or near a public or private area
• Possession of a component of an explosive or incendiary device with the intent to manufacture an explosive (15 counts)

There is no evidence presented to the grand jury or Walthour’s arrest reports indicating he was planning a specific event. However, investigators said all signs show he was in the process of planning a terror attack.

The Associated Press and NewsNation affiliate KLAS contributed to this report.