They say they have never seen anything like it before, and say neither have their counterparts across the country.
Police allege that on three separate occasions, the girls lured three female victims ranging from 13 to 17 years of age to a city residence for social reasons.
From there, the victims were driven to other locations for the purposes of prostitution.
The accused girls face multiple charges, including human trafficking, robbery, procuring, forcible confinement, sexual assault, assault, uttering threats and abduction.
Police are still looking for a third female suspect they say is age 17.
"Shocking is a great word, because that was our reaction," Staff Sgt. John McGetrick said in an interview.
McGetrick said he could not get into details of the case but said the victims were confined and somehow forced to engage in prostitution.
Police said there was no indication pimps or men played any role.
"We're not aware of anyone else involved," McGetrick said.
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