Complex sentence: Upon his release he begins a new career as a reporter for an independent newspaper, but also works as a vigilante who assists the police with their hard-to-prosecute cases (including cases where the accused are prominent and influential members of society).
Split into simpler sentences: Upon his release he begins a new career as a reporter for an independent newspaper. He doubles as a vigilante who assists the police with their hard-to-prosecute cases (including cases where the accused are prominent and influential members of society).