TechCrunch reports that Michael Goguen, a now-former managing partner at Sequoia Capital, is the target of a breach of contract complaint that includes allegations of sexual abuse over the course of 13 years. Goguen’s attorneys told TechCrunch that they will file a countersuit alleging extortion, while Sequoia Capital says Goguen has left the firm.

The complaint, filed March 8th, claims that Goguen’s accuser, Amber Laurel Baptiste, “has been a victim of human trafficking from the age of 15,”enduring violence, isolation, and starvation. It says that in the early 2000s, Baptiste met Goguen at a strip club in Texas, where she was a dancer. Goguen repeatedly asked her to dinner, and promised to help her escape her traffickers. But, in the suit’s words, “Goguen was a worse predator than the human traffickers who were keeping her in bondage.”

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According to the complaint, Goguen went on to pay Baptiste’s living expenses in exchange for maintaining their sexual relationship, while also marrying and divorcing two other women. The complaint alleges that the relationship included nonconsensual sex and “demeaning rituals,” and contains other extremely graphic and disturbing descriptions of alleged abuse.

Eventually, the lawsuit claims, Baptiste threatened to sue Goguen, but he talked her into a confidentiality agreement in exchange for $40 million. The current suit stems from Goguen allegedly reneging on that agreement. After making one $10 million payment in 2014, the complaint states that Goguen ceased payments, claiming the initial agreement was invalid because it was “procured under extortion.”

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Sequoia Capital has been investing in technology since 1972, and their portfolio includes companies from Apple APPL and Cisco CSCO to DoorDash and Evernote.

According to TechCrunch, Goguen’s countersuit will be filed on Monday.

Updated to add: Goguen has responded to the allegations in a post on LinkedIn. Read more about that here.