That was a better episode. Spoiler... I think that female cop will either be the serial killer or be a strong connection to them.
How is that a problem? I've never seen why people becoming annoyed at shows supposedly going on for too long. Once you don't enjoy watching a show anymore... stop watching it. Once I stop watching a show I don't care if it keeps going or not; it's of no consequence to me. If it picks up towards the end of the season.. that's a good thing, as it's definitely preferable to it tailing off or staying where it is.
Last season was the best yet and it keeps you watching this season because you are hopeful it will emulate the same greatness it had the previous season. Then the season picks up at the end and it becomes a repetitive cycle, frustrating you in the process.
That should only happen if you don't know it's happening though. If you think that's what happening, stop watching it. lol.
I know it is happens but I can't stop, which is why I will watch shows till the end, like Prison Break and Heroes even though they were absolute garbage in their last seasons.
