Who is Commissar Zhang Zhiqiang from Death of a Red Heroine and what is their importance?

Commissar Zhang Zhiqiang is an old Communist official. He is set in his ways and his thinking is rigid and predictable. Zhang is appointed adviser to Chen's unit. He insists on painstakingly following dead end leads and politicizing the case more than Chen and Yu believe is necessary. His first thought is always the good of the Party.