EXCLUSIVEJenni Rivera's former manager is on a rampage after the late singer's family published Jenni's biography -- claiming she's the REAL author ... and now, the manager wants at least $10 million.
Laura Lucio filed a lawsuit against Jenni's estate and family, claiming she managed Jenni since 2004 ... and during that time, she and Jenni co-authored the singer's bio --- "Mi Vida Loca" ("My Crazy Life").
Laura claims the book had several publish dates which were pushed back for different reasons -- and Jenni's sudden death in a freak plane crash in 2012 ultimately derailed the project.
Fast forward to July 2013 -- Laura claims Jenni's family somehow found the book on Jenni's computer and published it under a new title "Unbreakable" ... without so much as consulting Laura, let alone paying her.
Laura claims 95% of the book is her writings -- and under the deal she struck with Jenni, she's owed 40% of the book's profits. So far, Laura claims she's gotten squat.
Laura's now suing for at least $10,000,000. A rep for Jenni's estate says the family plans to fight the lawsuit.