25-year-old Edward Orth was arrested at the health club.
Based on the information FOX 10 has, it's not clear if any of the victims and their parents belong to the club or if any of the photos were taken there, but we know the suspect was part of the child care program at Lifetime Fitness in north Scottsdale.
Investigators say they first focused on Orth after looking in a file sharing website known to distribute child porn.
According to court documents they were able to identify an account used to post sexually suggestive images of minors.
33-images in all taken underwater at what appeared to be a public pool were posted in the "kids" and "nudity" section.
"I think it is not right, I think kids should feel safe in the company of an adult in a gym like this," said Catherine Clark.
Through surveillance, video investigators discovered their suspect worked at lifetime fitness in Scottsdale in the child care area of the club. One day they spotted him in the pool with a small group of children. Members FOX 10 spoke to were surprised to hear the news.
"As a parent I think they should definitely let the parents know what is going on. Especially the ones who have kids in swimming lessons and things like that," she said.
Orth was arrested at Lifetime Fitness, the club tells us they are committed operating a safe environment and "We are conducting an internal investigation as well as collaborating with the authorities in their investigation… the individual in question is not in a position to serve members in any capacity at this time."
Police also searched his car and his home where they found more questionable material.
Orth is being held on a $25,000 bond.