An appeals court in Switzerland has overturned a 2025 defamation conviction against a sleuth who had identified dozens of conference proceedings with signs of citation manipulation. The ruling orders the plaintiff to pay the sleuth’s legal expenses.
The judgment clears Solal Pirelli, a software engineer in Lausanne, in a lawsuit filed against him in 2023 by Shadi Aljawarneh, a computer scientist at the Jordan University of Science and Technology.
The case stemmed from a blog post Pirelli published in January 2023 summarizing problems with the proceedings of conferences organized under the auspices of the Association for Computing Machinery (ACM). Aljawarneh was the chair of most of the conferences, and the proceedings included signs of citation stuffing in Aljawarneh’s favor.
Aljawarneh filed his complaint against Pirelli in 2023 and, in June 2025, the Lausanne District Court found Pirelli guilty of defamation. According to the court, the blog post met the criteria for defamation because the “accusations are not limited to criticizing the quality of his work but clearly allege scientific fraud,” a DeepL translation of the latest judgment reads. Pirelli appealed the decision.
During the appeals process, ACM sent Pirelli a letter stating the organization had completed its investigation, the judgment states. The October 2025 letter indicated ACM found “clear and convincing evidence” that Aljawarneh had repeatedly violated ACM publication policies, according to the judgment.
Scott Delman, ACM’s director of publications, confirmed to us the organization retracted 38 papers in connection with the case. “There may have been additional papers investigated, but the ACM Publications Board found compelling evidence for the 38 papers that were retracted,” Delman told Retraction Watch.
The retractions prompted the Criminal Court of Appeals in the Swiss state of Vaud to overturn the district court’s decision in January of this year, and its detailed ruling was released May 1. “Based on [ACM’s] letter, it should be noted that the allegations made by the defendant [Pirelli] have been confirmed by the ACM and that the complainant’s [Aljawarneh’s] intentional conduct of falsifying and ‘inflating’ citations can indeed be broadly characterized as scientific fraud,” the judgment states.
Neither Aljawarneh nor his attorney, Fabien Rutz of Pyxis Law in Geneva, responded to a request for comment.
“I told the truth,” Pirelli told us. “That’s the defense against defamation, so I should be innocent if everything works.”
In 2022, Pirelli found anomalies in conference proceedings published by ACM and organized by the International Association of Researchers, or IARES. Those anomalies included citations to Aljawarneh in the front matter for the proceedings, papers that cited him over 100 times each, and a conference that allegedly took place in Kazakhstan during COVID-19 lockdowns.
Pirelli first reported some of the issues to ACM in October 2022, and later flagged more of the conference proceedings to the organization. When he didn’t hear from ACM, he went public with his findings in a blog post.
Aljawareh sent Pirelli an email soon after, asking him to take down the post. “My point of view has always been, if he had some concrete thing that I did wrong, he could have told me, which he did not,” Pirelli said. “Even when his lawyer sent me a letter, it was just like, ‘we think you are wrong.’”
Following the publication of the blog post, an April 2023 conference in which Aljawarneh was scheduled to participate was canceled, and he was removed from the editorial board of PeerJ Computer Science, the latest ruling states.
Pirelli learned in November 2023 that Aljawarneh had filed a lawsuit against him, which we covered at the time. Aljawarneh later submitted our article as evidence in his defamation claim. After the June 2025 ruling against Pirelli, Aljawarneh’s lawyers sent a letter to the Center for Scientific Integrity, the parent nonprofit of Retraction Watch, calling for us to remove the article, “which is detrimental to [Aljawarneh’s] honor and ruins his impeccable so-far academic reputation,” the letter stated. We neither removed the post nor responded to the letter.
According to the latest ruling, the letter ACM sent to Pirelli stated the organization concluded Aljawarneh “had engaged in citation inflation by adding unnecessary references to the introductory pages” for four conferences and “engaged in citation falsification by co-authoring papers containing an extremely high percentage of unnecessary citations of his own work,” among other findings. The court ruling also said ACM “imposed additional sanctions” on Aljawarneh. Delman declined to elaborate on what those sanctions were.
“While the burden of proof certainly lies with the defendant (Pirelli), one may nevertheless take into account the fact that the plaintiff has in no way substantiated his allegations regarding the proceedings brought against him by the ACM, even though he is the only one capable of producing evidence on this point,” the judgment states.
Delman of ACM confirmed the case “has now been concluded following an extensive appeals process.”
The court’s ruling states that Aljawarneh must now pay the defense the total expenses incurred during the first set of proceedings, 19,967 Swiss francs (roughly US$26,000) as well as the 7,044 Swiss francs (roughly US$9,000), for the appeal expenses. Aljawarneh has 30 days from the May 1 ruling to appeal the decision to the Swiss Federal Supreme Court.
The lawsuit has not stopped Pirelli from combing the literature looking for citation irregularities and fishy papers, mostly those published by ACM and IEEE.
“If there’s a paper in this or that journal that nobody reads anyway, I don’t really care,” he said. “But if there’s a paper in some conference proceedings published by the same publisher that publishes my papers, I feel bad. It’s like, well, what about my credibility if there’s a clown show next door?”
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