When does a crime become Qualified?

when it is attended by any aggravating circumstance or is expressly defined as such in the RPC...

why it is qualified? does it affect the nature of the crime?

it is qualified because the law says so.

yes, it affects the nature of the crime, particularly on how heavy or light the penalty would be.

(pinapahirapan mo ko lacson ah! personal opinion ko lang po)

supposed a crew of M/V Don XYZ, a fishing vessel destroy the cabinet of the ship captain and take some of his(captain) belongings including laptop, money and jewelry. what is the crime committed?

supposed, an NBI agent having no legal ground to arrest the the victim, threaten the victim and demanded sum of money for his release. what is the crime committed?