Desc: 508 Yi an: Directed by Tianren Wu. With Guanyin Ma, Jian Liu, Baolong Yang, Ning Ma. A murder occurs in a steel smelting workshop. The case becomes pended because of insufficiency of evidence. A smart and sturdy young policeman keeps on investigate the case and finds out the real murderer after several more relative murder cases. The murderer fabricated an approval ticket for stripping regulated materials.