Criminal has a firework that's not dangerous (11)

'criminal' is the definition.
(I know that safecracker is a type of thief)

'a firework that's not dangerous' is the wordplay.
I cannot really see how this works, but
'a' is present in the answer.
'firework' could be 'cracker' (cracker is a kind of firework) and 'cracker' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

'has' acts as a link.

Can you help me to learn more?