Douglas Haig, a 55-year-old aerospace engineer who sold ammunition as a hobby for about 25 years, said he met Stephen Paddock at a Phoenix gun show in the weeks before the Oct. 1 shooting in Las Vegas that killed 58 people and injured hundreds more.

He didn’t have the quantity of tracer ammunition on hand that Paddock was seeking, so Paddock contacted him a few days later and lined up a sale at Haig’s home in the Phoenix suburb of Mesa. Tracer bullets contain a pyrotechnic charge that illuminates the path of fired bullets so shooters can see whether their aim is correct.

Haig said he was shocked and sickened when a federal agent informed him of the massacre 11 hours after it unfolded. It’s unknown whether the ammunition he sold to Paddock was used in the attack.

“I had no contribution to what Paddock did,” Haig said, adding that there was nothing unusual about the type or quantity of ammunition Paddock bought. “I had no way to see into his mind.”

Haig held a news conference Friday in what his lawyer said was a bid to protect his reputation after he was revealed earlier this week to be a “person of interest” in the investigation. Haig’s identity emerged by mistake after his name was not redacted in court documents.