Bill Cosby's attorney sent a strongly-worded letter to CNN president Jeff Zucker this weekend, claiming that the network is ignoring the pro-Cosby sources he so graciously provided for a special on Cosby accuser Beverly Johnson.

Attorney Marty Singer writes:

We continue to be shocked by CNN's outrageous ongoing refusal to investigate and run balanced stories about my client. While airing untested stories from accusers who have seemingly been subject to little or no vetting, CNN takes the opposite approach with anyone who comes forward with relevant information undermining accusers' claims or with relevant information supporting Mr. Cosby.

You can read the entire letter, obtained by TMZ, here.

Singer is particularly annoyed that CNN seems to be ignoring and/or challenging claims from Mark Burk, who was Beverly Johnson's boyfriend in the late 2000s. Burk says that Johnson spoke highly of Cosby, and Singer feels this vague information should be highlighted in the special about Johnson. Singer provided CNN access to Burk as well as another source who could perhaps undermine Johnson's claims.

Calls for "balanced reporting" haven't worked for the Cosby camp before. Last week, National Association of Black Journalists President Bob Butler refuted Cosby's claim that black journalists should be "neutral" when reporting on Cosby's alleged crimes.