I think most people underestimate or undervalue the reliability of forensic evidence. For example, fiber is extremely precise to the point that even on the same shirt, we could find fibers that look completely different under microscope, even more so if fibers are from different shirts. That means it is incredibly unlikely for 歐陽炳強 to have a shirt with the same fiber structure as those found on the victim. Same goes for other evidence. Of course the evidence may not be professionally processed in 1974 but if they were, there are more than enough evidence to convict 歐陽炳強 with those forensic evidence, even today.
