If they signed up under the girls name;
They have commited fraud.
They have commited identity theft.
Not to mention posible libel.
If they posted naked prepubescent pictures, they also have violated child pornography laws.
I’m not sure the 1st Ammendment covers those activites.
They weren't charged with fraud, were they?
"They have commited identity theft."
They weren't charged with "identity theft".
"Not to mention posible libel."
Libel is a tort, not a crime - at least not since the US Revolution. You can't be "charged" with libel, or slander or defamation of character.
"If they posted naked prepubescent pictures, they also have violated child pornography laws."
Ashcroft v. Free Speech Coalition, 535 U.S. 234 (2002) struck down prohibitions of virtual child pornography. There's no child pornography case to be be made here, per the US Supreme Court.
Got anything else?