。
How suspect Miura has been spending his time in detention has come to light.
Literal
Miura suspect [of-の] in-detention [of-の] spending-way [subject-が] became-clear.
News register. 容疑者 'suspect' is the legal term for someone under criminal suspicion but not yet convicted; prefixed to a name (三浦容疑者 = 'suspect Miura') it's standard media practice. 拘置中 'during detention' uses the suffix ~中 'in the middle of' for ongoing states. ~方 attached to a verb-masu stem ('過ごし方' = 'way of spending/passing') forms nouns for methods or manner. 明らかになる 'to become clear / come to light' is a fixed phrase for information becoming public.