The National Review reported:
There is really no doubt that Cosby is guilty of being a sexual predator. The problem is that he was gulled into acknowledging this fact by a prosecutor, who had assured him that, the case against him being weak, he would not be charged. The hardest thing about being a prosecutor is that your two most basic responsibilities — proving the case and vindicating the accused’s constitutional protections — are in tension with each other. In this instance, the Pennsylvania prosecutors failed to respect the latter in pursuit of the former.
In a nutshell, relying on the assurance by the Montgomery County district attorney that he would not be prosecuted, Cosby agreed to testify in a civil case brought against him by Andrea Constand, then a Temple University employee whom he had sexually assaulted in 2004. Cosby made damaging admissions and paid a steep settlement.
Subsequently, political pressure to charge the actor had intensified
because numerous women made similar allegations that he abused them. The
alleged assaults followed a pattern in which Cosby would drug the
women, rendering them unable to resist. Meantime, Montgomery County had
gotten a new district attorney. In this spotlight, the new prosecutor
reneged on his predecessor’s non-prosecution assurance. The state
rationalized that, even if Cosby had in fact been assured of
non-prosecution and had acted on that commitment to his detriment, a
formal immunity agreement had not been perfected before a court. [https://www.nationalreview.com/2021/06/bill-cosby-freed-why-his-sexual-assault-convictions-were-thrown-out/?utm_source=zergnet.com&utm_medium=referral&utm_campaign=zergnet_6614071]