The teenagers- who live in Grandville, Michigan- posted images of a classmate performing oral sex on another teenager.
It also shows four other youngsters watching the sex act.
The images soon went viral and were posted on news sharing site Reddit, as well as social networking sites Twitter, Facebook and Instagram.
The website quickly removed the images after it became apparent that the girl in the photograph was under the legal age of consent.
Police have warned youngsters that sharing the images could result in a charge of distributing indecent images of children.
A spokesperson for the local police told a radio station: "No one should be sharing them."
Police Captain Kim Koster said: "The concern right now is the age of the people involved, consent is also an issue at times as well, so those are some things in any investigation like this one we'd have to determine."
The girl in the photograph has since taken to Twitter to defend herself over the images after being on the receiving end of cruel jibes.
She wrote: “Due to the fact that I put my business on the Internet for anyone and everyone to see, I can't and won't get offended by criticism.”
The teen then tweeted: “You gotta problem wit me then that's your problem (sic).”
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