Her sister Chynna Phillips is saying Mackenzie told her in 1997 about this. But Chynna's mother Michelle is denying everything.

http://www.usmagazine.com/celebritynews/news/chynna-phillips-2009239

His other ex-wife Geneviève Waïte was married with him during this and she's also attacking Mackenzie. She was also a major drug addict who didn't even raise her daughter Bijou. Bijou was raised mainly by her father, living on her own at 14, and of course was a drug addict herself. And if I remember correctly, Bijou has said her mother was a fucking mess and tried to kill Bijou with an axe chasing her around her home trying to kill her when she was a young girl. So who the hell is she to attack anyone's rape allegations?