This is another one of these that I didn't really remember. Ricker I kind of remembered, but I couldn't remember who was killing cops or why. Even when Eve figured it out, I still didn't remember.
Having cops killed always hits the other cops hard. It's even worse in this one, since it's cops being killed by a cop. Eve has some trouble with a cop who thinks Eve wants her job. She's a Captain with Illegals and works behind a desk. Eve is a street cop who hates desk work and doesn't really have anything to do with Illegals. No idea why Roth thought that, but that caused a bit of a problem.
Ricker was also a huge problem, but Roake playing a role at the end and making Ricker think he won was completely worth the issues the man caused.