I think we should separatedistinguish minor criminals andfrom hardened criminals.

Unless you mean that they should be physically separated, this is better.

First of all, for petty crimes like shopliftersing, we need to take triggers for the crime into consideration.

“Triggers” by itself sounds unclear. Alternatively, you could write “motivations” instead of “triggers”; I think that would actually be better.

Maybe they are starving and have no other way to feed their limselves, because they are not able to find jobs since they are from deprived backgrounds and are cannot accessible to decent education.

“Accessible” implies that the thing being described is the thing that is access.

In this case, administrationsthe government should provide them with job opportunities and education.

Or instead of “the government,” “social services,” depending on what you have in mind.

However, for hardened criminals like serial killers, nothing can be justified for them.

This is grammatical but I would write “their actions can have no justification” or “no leniency can be justified for them” instead for the second half, depending on the exact meaning you have on mind. As it currently is, it’s a bit vague and I’m not sure which idea you have in mind.

Finally, for juvenile crimes, police should always putkeep an eye on teenagers who drop out of schools or join gangs as they are in their formative years and too young to distinguish the right from wrong.

In this case, local governments should educate young offenders by providing some volunteer jobwork like community services, where they can gain happiness and a sense of fulfillment from extending a helping hand to feel a sense of fulfillment.

“Educate” implies an actual learning experience, and while it can definitely occur in community service, it’s not obvious here. Maybe “help rehabilitate” instead?

“Gain happiness” and “to feel a sense of fulfillment” mean similar things in this context, so I would condense them.

On top of that the governments should removexpunge their criminal record in case of theto avoid unfavorable effects on their later life.

“Expunge” is the technical term and also preferable (since the record still exists, it’s just not public and can generally be treated as nonexistent), unless you mean that the record really is completely gone.