The officer, Michael Anthony Carson, was arraigned on two counts of first-degree criminal sexual conduct Wednesday in Oakland County, FOX 2 has learned.
According to sources, the assaults have been going on for seven years. The minor is believed to be the only victim assaulted by Carson.
Carson is being held on a $750,000 cash/surety bond.
More charges could follow, as law enforcement from other jurisdictions are also investigation Carson's actions.
Detroit police are aware of the allegations but did not immediately provide a comment.
The department will request the Police Board of Commissioners move to suspend Carson without pay and health insurance.