Well. Historically, the Carabinieri were created as a military force with police duties (i.e. crowd control and suppression of civic unrest), which means their presence is very dense on the territory. There is no town, village, hamlet without at least one tiny Carabinieri post/detachment. They are also specifically trained against violent criminals.
So when a crime of violence is involved and time is critical, Carabinieri are probably the guys you want to call.