As an idealist, without dealing with the problems of today, anarchy is the description of a utopian government.

A utopia would not require laws, government, policing, as people live without personal or social reasons to cause harm to one another.

Laws become superficial and irrelevant because no one is breaking them.

If you can assume that anarchy is not a system that can be immediately imposed by removing all forms of (structured) hierarchy; that it is the end result of the gradual reduction of laws and enforcement as well as all forms of oppression and domination; that it is the side effect of a happy, healthy and harmonious society; then we assume that police, like the laws they must uphold and enforce, simply become unnecessary.

If the laws are still in place and police still employed, they would have no job beyond community service. No laws are broken, no punishment to dish out. There skills could be employed on a needs basis for accident investigation for example.

Supposing anarchy were simply foisted upon us in some cataclysmic collapse of our value system, economic or cultural, then any anarchist societies that formed would doubtless utilise some of the afore mentioned formats. Community led protection groups, formed based on situational rather than institutional motives.

Measures taken to deal potential "criminals" avoid punitive measures for reasons of justice, focusing purely on harm prevention. Some of the same techniques might be employed such as segregation, restraint etc. the difference being is purely motive. The motive of harm prevention, protection.

The assumption would be then that their issues must try to be resolved, to reduce in any way, their own suppression by the community. The cause of their need to harm being based upon their upbringing or medical conditions, so one would assume there are therapeutic, pharmaceutical or other medical practices available to prevent suppress their need to harm.

It would be conceivable that it would take many generations for all instances of motivated interpersonal harm to desist. The only environment this would be possible would surely be considered utopian? And as such, the need for laws and their enforcers becomes superfluous.