A journal received a paper that had previously been retracted from another publisher’s journal as a result of malpractice in the peer review process (a result of reviewer/editor misconduct rather than actions on the part of the authors).
Journal X was contacted by Author A, who claimed that a paper published in that journal ten years previously (by Author B) was plagiarised from Author A’s article in Journal Y published approximately ten years prior to that. Author A requested the retraction of Author B’s paper.