"There's some sick people on this case," Gmitter said.
Brown has been charged with endangering the welfare of a child, turned herself in Thursday and was being held in the Fayette County jail, police said. Brown's attorney did not return a call for comment.
Calloway faces several counts of attempted rape. He was arrested Wednesday and remains in jail. It was not immediately clear whether he had an attorney.
The three attacks occurred in Brown's home in Uniontown, about 50 miles south of Pittsburgh, according to the criminal complaint. The girl told police the plot was apparently hatched sometime in December after she rejected her mother's proposal that she allow Calloway to impregnate her and then marry him.
In the following months, Calloway tried to rape the girl three times, Gmitter said:
The first time, in February, the girl was alone with Calloway while her mother went out to buy pizza, according to the criminal complaint. Calloway began groping her and she kicked him away, the documents stated.
A few weeks later, the girl believes her mother spiked her Pepsi with rum, according to police. The girl told them she felt ill after drinking the Pepsi, passed out and vomited. She was partially naked when she woke up with Calloway in the room, according to the criminal complaint.
The third time occurred in mid-March, when the girl told police she came home early from school because she was not feeling well. She said that her mother forced her to drink tea.
The girl said she pretended she was asleep until Calloway made a move, at which point she bolted upright and he left the room.
In a search of the Brown residence, police said they found an empty rum bottle, Tylenol PM and a pill crusher.