A Flint man believed to be a serial rapist faces 27 more charges involving three of six victims.
Prosecutors accuse 60-year-old Gilbert Conway of kidnapping and sexually assaulting six women.
But there are worries there could be dozens, if not hundreds more.
He faces 77 felony charges, including those added on Tuesday, in the rapes that reportedly happened between 2009 and this year.
"It is very very difficult for somebody to come forward," said Genesee County Prosecutor David Leyton. "We've seen this through the (Brett) Kavanaugh hearings; we've seen this with other incidents... often are humiliated when they come forward. They suffer terrible consequences."
Officers are reviewing the contents of 500 videotapes found inside Conway's home when he was arrested earlier this year.
