Bill Cosby biographer sorry for omitting sexual assault allegations

The author of a new Bill Cosby biography is apologizing for not pursuing allegations that the comedian had drugged and sexually assaulted numerous women.

Mark Whitaker, whose 544-page "Cosby: His Life and Times" was published in September, tweeted Monday that he was wrong not to "aggressively" look into the charges and promised to address them "at the appropriate time."

"I was wrong to not deal with the sexual assault charges against Cosby and pursue them more aggressively," he tweeted to The New York Times' David Carr, in response to a story he wrote admitting to being one of Cosby's "media enablers" and calling out others for doing the same, including Whitaker.

"If true the stories are shocking and horrible," added Whitaker, whose account was confirmed by his publisher, Simon & Schuster, a division of CBS.

Reports about Cosby have been public knowledge for years, but resurfaced last month after a video of comedian Hannibal Buress calling Cosby a rapist went viral. With several additional women accusing Cosby of assaulting them (including former supermodel Janice Dickinson), projects on NBC and Netflix have been canceled, several stand-up dates have been scrapped and TV Land decided not to air reruns of "The Cosby Show."

Cosby, 77, has issued a statement denying the accusations.

Whitaker's book has been widely criticized for idealizing Cosby, until recently one of the country's most beloved entertainers, although some critics praised it upon release. Amazon.com included "Cosby" among its best books of September and top 100 biographies and memoirs of 2014. The book includes blurbs from David Letterman, Jerry Seinfeld and Mary Tyler Moore.

"If I was America's 'sweetheart' -- turning the world on with a smile -- then Bill Cosby was and still is our 'best man,'" Moore wrote.

"A revealing, honest look at my favorite comedian," reads a blurb from Billy Crystal.

According to Nielsen BookScan, which tracks around 80 percent of print sales, "Cosby" has sold around 6,000 copies. It's a small number for a well-publicized book, but not unusual in an increasingly tight market for hardcover nonfiction, which has been hurt by the decline of physical stores. As of midday Tuesday, "Cosby" ranked No. 13,711 on Amazon.

Cosby cooperated with Whitaker, agreeing to be interviewed. But, according to Simon & Schuster, Cosby had no control over the book's contents.