All other indications are that crime has been eliminated in Trek's time. On Earth, at least.
Well, TOS indicated that criminals were considered mentally ill and put into asylums, with good results (until Dr. Adams overdid it a bit in "Dagger of the Mind"), and with only one asylum's worth of incurables in the entire Federation (Elba II in "Whom Gods Destroy"). There were no other known civilian punishments such as fines or prison sentences in evidence. But certainly one would need law enforcers in order to catch the villains and to force them to undergo the therapy.
TNG "Justice" suggested that people were screened against criminal tendencies in their youth, while the 24th century spinoffs generally maintained that the consequence for all criminal behavior was forced therapy, usually six months of it (supposedly involving closed environs such as penal colonies). And such therapy seemed to be a success, or at least there were no known repeat offenders. Hey, even Harry Mudd had never exactly
repeated a previous offense! Again, no mention of fines or jail sentences in modern Trek, but once more there would be a definite need for a police force.
Starfleet maintained traditional courts of law for its internal affairs, and at various points of its history also upheld the death penalty. Whether there existed civilian courts is unknown. It would be a bit odd if a court of law was called to judge on what was accepted as a medical case - but a court of law might be a filter that would examine a case and decide whether it involved a crime (that is, a mental illness, in which case the accused/patient would immediately be shipped off to his or her standard six months of therapy) or a mere dispute (something the court had the authority to handle).
Edit: Oh, and thanks for pointing out that the badge
can be seen. Curiously enough, the symbol on it looks very much like a big letter A - or, in other words, the Starfleet delta...
Timo Saloniemi
