Musk understood it to be a venture capital-hosted costume party.

Musk’s attendance was originally reported by Business Insider.

In an email, Musk’s spokesperson wrote: “Elon was at the party for a couple hours and left around 1 a.m. after talking with several DFJ-funded entrepreneurs about technology and building companies. His impression was that it was a corporate party with a costume theme, not a “sex party,” and there was no indication that it would become one after he left.”

The Silicon party scene, featuring attendance by some of the most powerful men in tech and investing circles, are regular, exclusive, and sometimes sex- or drug-fueled events, according to Bloomberg reporter Emily Chang’s forthcoming book, Brotopia: Breaking Up the Boys’ Club of Silicon Valley. Excerpted in Vanity Fair on Tuesday, the book will be released Feb. 6 by Portfolio, an imprint of Penguin Publishing Group.

Axios identified the home in the excerpt as Jurvetson’s residence. A separate blog post by entrepreneur Paul Biggar said that he didn’t observe any sexual activities at the event. Two other attendees in addition to Musk said on the record that they didn’t see any sex.

In November, Jurvetson stepped down from his venture firm Draper Fisher Jurvetson as well as took leave from the boards of Tesla and SpaceX, following an internal investigation.

DFJ issued a statement at the time saying that Jurvetson and the VC firm parted ways “by mutual agreement.”

“DFJ’s culture has been, and will continue to be, built on the values of respect and integrity in all of our interactions,” a DFJ spokesperson said. “We are focused on the success of our portfolio companies, as well as the long-term vision for the firm and will continue to operate with the highest professional standards.”

The firm’s did not reveal the reason for Jurvetson’s departure. But anonymous sources cited by Recode said “the investigation uncovered behaviors by Jurvetson that were unacceptable related to a negative tone toward women entrepreneurs.”