Officers said they observed a car parked in an alley on the 10200 block of Central Avenue at about 9 a.m. Sunday. Mark Michaels, 53, was taken into custody after officers allegedly saw him performing a sexual act on the girl.
"During the investigation, [an officer] contacted both parties and determined there was an inappropriate sexual activity occurring between the two," said Montclair Police Lt. Jason Reed. "The subject was ultimately arrested booked at West Valley Detention Center."
The incident happened about an hour before service at Bethany Baptist was under way. The alleged victim is involved in the choir at Bethany Baptist.
Michaels, 53, has been the choir director at the church for the past four years, where his wife plays piano. Church elders fired Michaels in the wake of the incident.
Michaels was supposed to be in San Diego Sunday. His wife was at their Upland home ill at the time of the alleged incident.
Police say Michaels had known the victim for two years. The girl is the only minor in the choir.
Senior Pastor Josh Matlock said the news came as a shock to the entire congregation.
"It has hit me and others in the congregation that found out like a ton of bricks. Big shot to the stomach," said Matlock. "Blindsided. Didn't see any of this coming.
"We're just hurting by this. All parties are hurt and this is all families that we've loved and care about," said Matlock.
Michaels was held at the West Valley Detention Center on $50,000 bail.
Investigators are trying to determine if there are more victims. Anyone with information related to the case is urged to call the Montclair Police Department at (909) 621-4771.