AURORA, Colo. (CBS4) – Aurora police have arrested a soccer coach and have accused him of sexual assault on a child.

Investigators say Marc Pereira, 28, had an on-going sexual relationship with a teenage girl who played for him. He’s been a coach with the Rocky Mountain Soccer Academy for the past several years.

Pereira was arrested Thursday night. Police say the victim is a 15- to 17-year-old Aurora girl.

“Even in a case like this, if it is consensual, you can’t do that when you’re in a position of trust like that,” Officer Frank Fania with Aurora police said.

Some neighbors watched as Pereira was arrested in his Aurora neighborhood on Thursday.

“Shock really is the only thing I can express now,” neighbor Jason Arrington said.

A third party went to police about the relationship. Sources close to the investigation say they are having a difficult time because the girl’s family is not cooperating. Pereira had coached her through Rocky Mountain Soccer Academy for at least three years. His father is the president of the organization and calls for comment were not returned. Now police want to make sure there are no other victims.

“Just because he’s been a soccer coach for so long,” Fania said.

Pereira’s neighbors say they are concerned and will be watching their children extra closely.

“You hear about these things going on and it kind of hits home,” neighbor Steve Johnson said. “You don’t think this kind of stuff is going to happen around you. It can happen anywhere, I guess.”

Pereira is already out of jail on $50,000 bond.

Police say anyone with information about other possible victims should contact them.