Cassie says Diddy is fishing around, demanding she turn over her bank statements and a book she wrote about him … and she wants a judge to put the kibosh on his legal request.

According to new legal docs, obtained by TMZ, Cassie is trying to get the court to kill a subpoena she claims she was served by Diddy’s legal team.

Cassie says Diddy sent her a subpoena March 19 demanding she turn over “all draft memoirs, autobiographies, narratives, diaries, journals or notes … and any communications about plans to publish or threaten to publish such a document.”

The subpoena is interesting on a couple levels … because earlier in Diddy’s case one of his attorneys, Marc Agnifilo, claimed Cassie had told Diddy she had written a book about him that he could “catch and kill” for $30 million.

Agnifilo claimed back in September that Cassie had her lawyer call Diddy’s lawyer on a recorded line informing him she had written a book about their relationship that she planned to publish. Agnifilo also claimed Cassie indicated to Diddy he could buy the rights to the book for $30 million to prevent it from being published.

Thing is … Agnifilo claimed Diddy balked at the alleged offer. He claims Cassie switched lawyers and her new attorney told Diddy in November 2023 that the book was no longer important because a civil sex case was going to be filed.

As you know … Cassie ended up suing Diddy for rape and abuse, and the day after she filed they reached a settlement.