Speculation: IRPF’s full name is the Inner Ring Police Force. They were established after Ganymede colony, and during the same period as the colonization of Europa.
The name suggests that, at least initially, there was no protection for the colonies outside the orbit of Mars. The game author confirms this in a chat: IRPF’s initial mission focused on the inner ring. Europa was effectively a corptown with no outside interference, and governed itself, and Ganymede was, at the time, fiercely independent and lawless.
This almost certainly feeds into Ganymede’s reputation as the best place in Sol to hide a body. There’s no record of when IRPF’s charter expands to the Jovian colony, but the strife created by Vitae (both the rift between TTI and Progenitus and the obvious game-changing threat of a supersoldier serum) likely creates the need for more Europan protection and oversight, likely around 483.