Complex sentence: By some accounts DiBernardo was "the" major figure behind the US adult industry, he was a relatively capable businessman who did not have any personal reputation for involvement in violence, but his Mafia links deterred potential competitors and warded off other criminals.
Split into simpler sentences: By some accounts DiBernardo was "the" major figure behind the US adult industry. In any events he was a relatively capable businessman who did not have any personal reputation for involvement in violence, but his Mafia links deterred potential competitors and warded off other criminals.