Based solely on the sentence you provided, it difficult to tell you which tense to use. I would need to know the context.
However, I don't think that the choice of tense is your main issue here. It is incorrect to say "these investigations have seen..." because investigations are incapable of performing an action or having a feeling. I used to make this mistake a lot!! To correctly reword your sentence you could say, "as a result of these investigations, several officers were arrested." You could also say, "throughout these investigations, several officers have been arrested." These two example sentences also give you the option of past or present perfect tense. Determining which of the two sentences is better just depends on the context of what you are writing about and your personal preference.
I know that last part wasn't a response to the question you actually asked, but I used to make that same mistake all of the time and wanted to help!