Britt was one of seven (?) KILLED. Heather was an equal opportunity stalker/killer.
There is no way Heather would have been set free after killing multiple people. The best that could happen is being sent to a less severe prison.
HOWEVER, this is a soap and with Ryan totally and completely dead, the show is down one deranged character. And the actress playing Heather has a good time playing the role which translates into her being fun to watch. So while it is totally unbelievable for real life, I can be a good sport having her back on the show as long as they integrate her slowly back onto the show giving her secondary relationships that show different sides of the character before she goes off the rails again.
As always it comes down to execution.
Karen L.
