In Russia if you have your own company, store, some kind of business then you have to pay Russian Mafia some percent that they ask you to pay them from the money you earn of the business and if you dont then your either getting capped or being taught a lesson so and when you do pay them then they "got your back" from other Russian Mafias.
So Im sure Prokhorov was/still is involved with some Russian Mafia because he paid him and they had his back.

Cops cant do about these Mafias cuz they scared of em.