MONROE (WWJ/AP) – The owner of a music store in Monroe has been charged with sexually assaulting two teenage boys.

Police say 50-year-old Robert Stumpmier, the founding member of a 4-H music club who also owns Power Play Music, used his position of leadership and authority to coerce his victims. He’s facing multiple charges that include accosting and soliciting a minor for immoral purposes, and third-degree criminal sexual conduct.

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Detective J.D. Wall said the assaults took place either at the music shop, located on South Monroe at East 1st Street, or during an out-of-state trip.

Investigators say the sexual assaults followed months of “grooming behavior.” According to court documents, the alleged assaults on one of the victims began in Jan. 2012, when he was 14-years-old, and continued until recently.

Wall told the Monroe News that a second victim came forward after the initial charges were filed. He said the victims are now 15- and 16-years-old.

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Nathaniel Rumbarger (Booking Photo)

Nathaniel Rumbarger (Booking Photo)

A former store employee, 21-year-old Nathaniel Rumbarger, is also facing a third-degree criminal sexual conduct charge in connection with the case.

Rumbarger, of Luna Pier, is free on bond. Stumpmier, of South Rockwood, remains jailed on the charges. Both are scheduled to be in court on March 3.

Wall said investigators are still looking to identify any additional victims. Anyone with information is urged to contact police at 734-243-7509.

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