How did it come ____ that the police were involved?

Come about (Phrasal Verb)
English Meaning: to happen, or start to happen.
Bangla Meaning: ঘটা
Example:
- How did the problem come about in the first place?
- How did such a confused situation come about?
- She was late again, but I'm not sure how it came about this time.
- How did it come about that the police were involved?
In the context of the sentence, only 'about' is appropriate.

Source: Cambridge Dictionary