A registered sex offender is in jail for allegedly violating his probation by giving minors piano lessons, Channel 2 Action News reported. A mother said she found his name on the sex offender registry and called authorities.

Robert H. Green, 55, is accused of giving children music lessons for years, but he's serving five years' probation after pleading guilty in 2009 to child molestation, aggravated sexual battery and giving alcohol to a minor, the report said.

Rina Buckner told Channel 2 that after she hired Green to give her daughter piano lessons, Green bought the teen a piano stand, offered her work as a teaching assistant and asked to take her on day trips to play in Athens. The invitations triggered her suspicions.

"I said let me look him up because I need to investigate and see who this guy really is," Buckner told Channel 2.

That's when she found Green's name on the sex offender registry, and "my jaw hit the floor," she said.

Buckner called authorities, including Green's probation officer.

Now Green is in the DeKalb County Jail charged with violating his probation, which prohibits contact with minors.