'The Playboy Murders' Finale: Bridget Marquardt Makes Surprise Appearance (Exclusive)

The season 2 finale of the Investigation Discovery series premieres Monday, March 11.

Hugh Hefner's ex-girlfriend, Bridget Marquardt, is set to make a surprise appearance in the season 2 finale of The Playboy Murders.

In an ET exclusive preview of the finale set to air March 11 on Investigation Discovery, Marquardt shares in an interview what women were expected of them if they ever ventured upstairs and into Hefner's bedroom at the famed Playboy mansion.

"At the end of a club night, if you come up to the bedroom with everybody there is a certain level of expectation that you are agreeing to participate," Marquardt says. "There's no forced participation or anything like that. But it's very frowned upon and spectate."

In the preview clip, a journalist then talks about Jill Ann Spaulding, a professional poker player turned Playboy model who wrote a tell-all memoir exposing the secrets of the mansion, before becoming involved in a deadly love triangle.

"Hefner is really starting to pay attention to Jill Ann," says writer Audra Heinrichs. "And he's telling other women in the group, 'I want to have sex with Jill Ann in the group tonight.' And so, that expectation is now there. In her mind, Jill Ann is truly worried that there's a reality in which she refuses sex with Hefner and he would force her, and she would be raped essentially, and all of these other women would be participants in that. This is not what she had in mind at all."

Marquardt, the former Girls Next Door star, dated the Playboy mogul from 2002 to 2009. She starred alongside Hefner's two other girlfriends at the time, Kendra Wilkinson and Holly Madison, who is behind the Investigation Discovery series.

It's not the first time a former Hefner partner opened up about the expectations the late Playboy mogul set at his mansion. His widow, Crystal Hefner, recently wrote about it in her book, Only Say Good Things: Surviving Playboy and Finding Myself.

Crystal claimed in her book that the first night they met -- at a Halloween party at the mansion -- she was picked to join Hefner and a group of women upstairs for a night of debauchery that included weed and sex.

"This was a well-oiled and well-practiced sequence of events. One that went the same exact way every time," Crystal writes in her book. "Picking some girls from the party and bringing them up. Changing into the uniform for the job: silk pajamas. The dimming of the lights. The music. The porn. Passing the pot. And then the sex."

The season 2 finale of The Playboy Murders airs Monday, March 11 on Investigation Discovery.

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