The "Murder Club" series, also known as the "Thursday Murder Club" series, features four main characters:
* Elizabeth "Liz" Green: A retired nurse and the founder of the group.
* Joyce "Joyce" Hare: A retired history professor who brings her keen knowledge and love of mystery to the club.
* Ron "Ron" Ritchie: A former psychiatrist who provides a unique perspective on the human psyche.
* Ibrahim "Ibrahim" Khan: A retired detective who brings his professional experience to the club.
There is no character named Jill Bernhardt in the series. Could you be thinking of another book series or character?