I shared a derivative book I made without authorization just to share a concise version of the original book with my students. This was plenty of years ago, approximately six years from now. I recently realized that the students published my summary version of the book, which has my name all over it in websites like Slideshare and Scribd. Since then I've been concerned about a possible legal demand coming from the editorial if they realize that there's a summary copy of their book online with my name on it. Is there a fixed amount of time in which the crime must be ignored even if the editorial realizes it?. The illegal derivative work was made six years ago, I've read that after ten years the offense cannot be considered for trial. Is that true?
Under 17 USC 507, the limit depends on whether this is criminal prosecution versus a civil action. Criminal prosecution must be "commenced within 5 years after the cause of action arose". A civil action must be "commenced within three years after the claim accrued". The courts do not entirely agree on what that means, in particular whether that means 3 years from discovery of the infringement (the majority opinion: the "discovery rule" see Warren Freedenfeld Assocs., Inc. v. McTigue, 531 F.3d 38), or from the infringing act (the "injury rule" which has been employed in the 2nd Circuit and perhaps only there, see Auscape Int'l v. Nat'l Geographic Soc'y, 409 F.Supp.2d 235; undecided in the 11th Circuit). Discovery might mean "or should have discovered", following Sieger Suarez v Arquitectonica Int’l, 998 F.Supp.2d 134 ('"Should have learned," means whether a reasonably prudent person in Plaintiff's position would have become aware of the alleged infringement').
So, no to the number 10. If the plaintiff knew and ignored and the act was 6 years ago, that is past the limit. If the plaintiff did not know until recently (someone just emailed them the info), that would be within the limit, in the majority of jurisdictions.
(One other complication is whether the limit would be extended under the doctrine of equitable tolling, but that seems unlikely given the circumstances described: the plaintiff was not prevented from pursuing a remedy, there was no concealment by the author).