I just went back and checked. You are correct - PBC and LotF were explicitly stated to be 3rd and 1st, respectively, while Caia's ranking was not given. I assumed Caia was 2nd considering the mods talked about how 1 more arrest would effectively dismantle the gang.
One thing to consider is that the write-up definitely said that the police had access to that gang's records after Caia died. You might want to investigate who inherited Caia's role.
@StartingoverVet,
@WildZoo, were either of you told about consequences for losing your 4 members? I'm trying to figure out if the chief's talk of "dismantling" is flavor or reflects in-game consequences.