Douglas Haig was considered a "person of interest" after his fingerprints were found on the "armor-piercing" bullets Stephen Paddock used to kill 58 people at a country music festival.
Paddock was later found dead with a self-inflicted gunshot wound. Haig was charged shortly before a news conference Friday, where he told reporters his first meeting with Paddock in August of last year did not raise any suspicions.
A few days later Haig sold Paddock 720 rounds of what he described as "un-modified" tracer ammunition.
"Yes, he said that he was going to go out the desert and put on a light show either with or for his friends. I can't remember whether he used the word 'with' or 'for,' but he said that he was going to go out and shoot it at night with friends," Haig said.
The complaint filed Friday, in federal court in Phoenix, says Haig didn't have a license to manufacture armor-piercing ammunition.
Haig is a 55-year-old aerospace engineer who sold ammunition as a hobby for about 25 years.