Criminal investigation is a science and follows the scientific method of developing sensible hypotheses, testing it with reliable evidence, and forming logical conclusions on these bases (among other steps). Therefore, perhaps, it is not surprising that Filipinos suck at it. It is because we as a society hopelessly lack a strong (or even at best a mediocre) track record of scientific achievement and possess a severely stunted ability to think critically.
Indeed, even within the ASEAN region, the Philippines sorely lags behind Malaysia and Thailand in the publication of scientific and research papers. The Land of Manny Pacquiao is, in recent years, also fast being outpaced by historic basketcases -- now emerging economy posterboys -- Indonesia and Vietnam.
Using Science Citation Index Expanded, Katherine Bagarinao reviewed the publication performance (number of indexed articles) of five ASEAN countries from 1980 to 2006. She has shown with graphs that Thailand and Malaysia were ahead of the Philippines from 1980 (Fig. 3A), but the Philippines was ahead of Indonesia and Vietnam. The Philippines, however, was overtaken by Indonesia in the mid 1990s and by Vietnam in mid 2000s in number of publications (Fig. 3B). The Philippines is not only behind in publications, but it has also shown the slowest growth rate among the five countries throughout the covered period.
Normally it is hard to convict a murder suspect -- specially if the sentence is severe -- because the guilt of the accused needs to be proven beyond reasonable doubt. And even if the volume of alternatives mount (perhaps due to unsound witness accounts) these alternatives need to be rigourously ruled out.
Reasonable doubt, rigour, and alternatives. One needs an open mind to consider these. Unfortunately Filipino culture is renowned for an utter lack of any of these, being a people renowned for their quickness to judge on the basis of mere speculation and popular hearsay. As such, it is possible that the horrible prospect of large numbers of innocent men and women languishing in Philippine prisons blights the holier-than-thou character that forms an immense chunk of Da Pinoy's self-perception.
Hubert Webb et al certainly falls under that subset of possible victims of the banal injustice that describes the Filipino Way of Life. Worse, the status of the more tangible victims of all this -- the Vizcondes -- has not changed.