The antitrust pitchforks are out for big tech. First came the European Union, then Washington, DC. Not to be left out, now comes hip hop lyrics.

Over the weekend, the music annotation site Genius publicly accused search juggernaut Google of stealing its crowdsourced song transcripts and natively publishing them on its search pages in knowledge panels Google calls its “One Box.” Doing so, Genius alleges, hurts Genius’ bottom line by diverting traffic away from Genius in favor of keeping people on Google’s monetized search page instead. As Genius sees it, this is an example not just of lyric lifting but of Google using its scale to unfairly home in on a smaller competitor’s territory, which experts say could constitute a potential antitrust matter. Google strongly denies all of it, blaming a contractor for any similarity between its lyrics and Genius’.

Emily Dreyfuss covers the intersection of tech and culture for WIRED.

How could Genius be so sure the lyrics on Google came from its community? Its engineers employed a clever trick, as The Wall Street Journal reported: They boobytrapped a selection of their transcripts, secretly embedding a watermark in order to track who copied their lyrics across the web.

Beginning on an occasional basis in 2016 when it first worried Google was copying its lyrics and sent the company a letter asking it to stop, and then ramping up last year into a systemic approach, Genius engineers alternated a pattern of straight and curly apostrophes in the transcripts that in Morse code reads out the phrase “red handed.” Genius sent 100 examples of transcripts it says it found on Google with the watermark to Journal reporters, who verified that the secret code was present in three songs randomly picked from that bunch.

But the day after the story published, Genius noticed something: The watermark had disappeared on most of those lyrics now on Google. Now, for most of the 100 songs that Genius had sent the Journal, all the apostrophes are straight in Google results. Had Google tried to scrub the evidence of its pilfering? That’s how it seems to Genius. "Google has known exactly what is going on for two years,” says Ben Gross, Genius' chief strategy officer. “Now that the issue is public, they are apparently removing evidence of their behavior without addressing the underlying problem. Google is still displaying lyrics copied from Genius.”

The engineering team at Genius has been keeping track of what appears on Google lyrics One Boxes since last October, scraping and caching hundreds of Google song lyrics results every day. So they went and looked back at the daily caches to see when the watermark disappeared. They found that the watermark had been present on all the sample lyrics until June 12, and then it disappeared on June 13. WIRED examined the HTML of a random selection of these cached pages, and they do appear to show the watermark present until June 12. Though the WSJ story published on June 16, Genius says it had been in contact with WSJ reporters before June 12, raising the possibility that the watermark was scrubbed after being reached for comment by journalists.

When reached for comment, Google denied making any changes. A spokesperson for Google insists the company doesn’t create any lyric transcripts itself or scrape any websites for lyrics, relying instead on multiple third-party providers to source song lyrics for its knowledge boxes. It pointed WIRED to Canadian-based lyric transcription service LyricFind, which on Monday publicly took the blame for the Genius watermark showing up on Google Search pages (while refuting the framing of most of the reporting on the issue).

“It's basically indisputable that this Google contractor LyricFind was just copying their lyrics from Genius,” says John Bergmayer, senior counsel at the nonprofit Public Knowledge, who has worked on numerous antitrust issues involving Google and has been watching the Genius allegations closely. LyricFind says it previously used Genius as a legitimate “reference” for its transcriptions, as it did many other sources, and is now reassessing that practice.