Q: We suspect plagiarism by a referee
We proposed a referee candidate when submitting a manuscript. In the manuscript, we modified the past theory by the referee candidate and indicated an extension of the results. Our manuscript was rejected, but almost at the same time, the correction of the referee candidate’s paper was published online. The method of correction is essentially the same with our rejected manuscript. We are suspecting a plagiarism by the referee candidate, but we don't have clear evidence of plagiarism. How can we contact the editor in this case?
Thank you for your query, and we are very sorry to hear that this occurred! I agree that the timing of these events makes it reasonable to question whether there was any unethical behavior on the part of the individuals concerned, but the seriousness of this allegation means that it would be prudent to tread carefully. A reasonable course of action would be to contact the editor explaining your concerns that a publication with similar content to your submission was published at a similar time frame to when your manuscript was submitted, and noting that you hope the editor will be able to rule out any influence of your submission on the publication of this correction. The hope is that the implicit assumption of good faith will balance out the seriousness of the allegation and hopefully bring any such event to light. As you noted, because there is no direct evidence of plagiarism, it is difficult to proceed more decisively than this.