Pauley Perrette‘s final NCIS episode as beloved character Abby Sciuto just aired last week, and already the actor is publicly hinting at possible reasons for her departure.

Perrette, 49, starred on NCIS for 15 seasons, and has never stated exactly why she left the show.

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On May 13, Perrette posted a series of cryptic tweets, referring to “multiple physical assaults” and “bullying.” Though she didn’t state any accusations outright, she also made reference to a “machine keeping [her] silent.”

The Twitter rant begins with Perrette discussing some tabloid articles about her — it’s unclear which ones — but the actor seems to be saying that she somehow suffered abuse during her time on the show. Whether she was subjected to harm in her personal or professional life also isn’t specified, though her mention of her “crew, jobs and so many people” seems to indicate the set of NCIS itself rather than any relationship issues.

There have been rumours of a clash between Perrette and former NCIS costar Mark Harmon, who supposedly brought his rescue dog on-set despite its vicious past; the dog bit a crew member in October 2016, resulting in the need for stitches. Harmon’s disregard for other people reportedly perturbed Perrette, but this has not been confirmed as the cause for her Twitter messages or her departure.

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Despite Perrette taking a new path in her life, she was still upset that she was leaving the role, as she told CBS News.

“It makes me sad to imagine a world without Abby in it,” Perrette said. “It really makes me sad.”

The show has seen many cast departures over the last few seasons: Cote de Pablo (Ziva David) left NCIS at the beginning of Season 11, Michael Weatherly (Anthony DiNozzo) left to star in Bull at the end of Season 13 and Jennifer Esposito (Alexandra Quinn) only starred on the show for one year.

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“We’ve known for some time this would be Pauley’s final season on NCIS and have been working toward a special sendoff. From day one, she has brought incredible passion and specificity to the role. Abby is a character that inspires millions of fans around the world, and all of us at NCIS are appreciative of Pauley for portraying her,” said NCIS executive producers George Schenck and Frank Cardea in a statement.

Neither U.S. broadcasting network CBS or Perrette has revealed the exact reason for her departure from NCIS, though when she announced in October of last year that she’d be leaving, she reiterated that it had nothing to do with any relationship breakdown between her and CBS.

‘NCIS’ airs on Global on Tuesdays at 8 p.m. ET/PT.

Global News has reached out to Perrette and her team for further comment.