Douglas Haig, who had been called a person of interest in the investigation, faces a charge of conspiracy to manufacture and sell armor-piercing ammunition while not being licensed to do so.
However, among the unfired rounds found in Paddock's hotel room were two cartridges which forensic analysis determined were armor-piercing/incendiary ammo that had Haig's fingerprints on them, the complaint states.
Mr Haig said he didn't believe Paddock had used the ammunition he had supplied, which were tracer bullets that leave a fiery trail behind them.
Haig said Paddock was well-dressed, polite, and did not raise any suspicions when he purchased ammuniations rounds from him..
Haig said he was sickened when a federal agent told him of the massacre hours after it happened.
He appeared in court Friday and was released under the condition he not possess guns or ammunition.
Neither Haig nor his lawyer could be reached for immediate comment after news of the criminal case broke Friday afternoon.
He didn't have the quantity of tracer ammunition on hand that Paddock was seeking, so Paddock contacted him several days later and lined up a sale at Haig's home. His attorney said the ammunition had not been altered at all.
Did the Groundhog See His Shadow Today?
Groundhog Day is of course observed in other locations in Pennsylvannia, as well as New York, Texas, Ontario and Nova Scotia. Let's be clear, taken at face value, they're not. "He issued this proclamation on Candlemas , and yes, Groundhog Day".
"I hope today ends (the death threats), when people realize that I wasn't in collusion with Paddock - that I was not in any way, shape or form associated with the terrible crime that he committed", Haig said.
According to the Metropolitan Police Department document, prepared in October, "Until the investigation can rule otherwise, Marilou Danley and Douglas Haig have become persons of interest who may have conspired with Stephen Paddock to commit Murder with a Deadly Weapon". Haig's identity emerged by mistake after his name was not redacted in court documents.
'He said that he was going to go out and shoot it at night with friends, ' Haig said.
Speaking of the bullets which contain a pyrotechnic charge that illuminates the path of fired bullets, Haig said, 'You would have seen red streaks coming from the window'.
"I have to trust them", Haig said of those customers.
Haig said nothing out of the ordinary occurred during the brief transaction.
Haig, 55, of Mesa, Ariz., is a senior engineer for Honeywell Aerospace, an aircraft engines and avionics manufacturer in Phoenix.
"I had no contribution to what Paddock did", Haig said.
Records show Haig also owns Specialized Military Ammunition LLC. "I had no way to see into his mind. I'm a vendor, a merchant whose name was released", he told reporters.