What's the deal with the chemist in the film?

Lol its 2016, but i have time so I'll explain you.
Police was reformed, so they changed structure and people too.
Olo wasnt re-employed, Franz was, besides Olo got nice cash to do it.
Firstly, Olo planned to be plug in gang to get exhibits, proves and get back for this his previous job, but I guess he scared major Gross so badly that he was participating in their crimes. Olo also banged Franz's girlfriend. Franz tried help him get his job back, but discovered that he *beep* Andżela and Olo crossed thin line between gang and police job he was one of gangsters. These things leaded to this situation that friendship lost. If you read this, sorry for mistakes english its not my fluent language.