Either 'commit' [present tense, indicating current or future actions] or 'have committed' [present perfect, for past actions up to the present] are good, and essentially mean the same, unless there is something in the narrative to suggest that the situation is changing or is about to change.

A

If you correct the spelling (committed), both possibilities are fine, but the meanings are different. Using ‘Commit’ makes it a very general statement not linked to a specific time period. ‘Committed’ would be used to talk about specific crimes that we are already talking about which have taken place in the relatively recent past. ‘have committed’ is even more general. For example, it covers someone who committed a crime 50 years ago. You need to supply more context to clarify what you are talking about.

B

Both are tolerable. But "commit" is the better option here, because "committed" should have a double "t", and would ideally be preceded by the word "have".