The lovable serial killing villain has a day job with the fictitious Miami Metro Police as a blood pattern analyst. So what the heck does that mean? The pictures below shed some light on what Dexter does in his professional capacity.
*All pictures stolen from here, original source is this.
Television shows like the CSI franchise sold us on the idea that forensic science can solve almost anything. To certain extent, science have made crime investigation a lot more reliable than the previous method of beating up a suspect until he/she confessed (though it's still applied in parts of the world where civil liberty is still a laughable dream). As much as the television show has done to encourage interest in science, it has as much to do with real-life laboratory practice as porn is to making love. My friends and I often laugh at the insane timeline portrayed in CSI (collecting specimen, tagging and paperwork, sample prep, sample run AND analysis in a single day? Please.) and we mock at the clean chromatography results (yeah, nice, distinguishable peaks from a swab at the freeway. Riiiiight.). Not to mention the awkward pipetting techniques or the blase centrifuging without balancing the rotor. To have someone comment, "You're doing it the CSI-style, aren't you?" is considered as a gross insult.
Science, however, is not infallible; DNA profiling is not the magic bullet of conviction as evidenced by the inability to distinguish the rapist twin from the innocent one (though this may change). Samples degrade, there are issues of contamination, false evidence, specimen tampering and many more. That said, it doesn't mean that you can call a video iron (refer to comment by Tuan Guru Haji Hadi Awang on Anwar Ibrahim's Chinadoll video) and throw science out of the window. DNA technology has helped to overthrow convictions on people wrongly imprisoned for rape and give names and faces to victims of mass disasters. Surveillance technology helped to map the unfolding of the Boston marathon bombing step-by-step. Biometrics have been invaluable in enhancing security protocols as well as identify presence at a crime scene.
However, as more and more criminals and villains get smarter from watching Discovery Channel and use forensic science against the law enforcement, legal technicality gets a lot more convoluted and conviction remains equal parts of science, good investigation, robust prosecution and a huge dollop of luck.