Bit unsure about the blacklight thing, blood under UV does not glow they use a chemical like luminol of that afaik. ALS(Alternative Light Source) and blacklight are the same thing, technically at least, ALS has narrow wavelength spectrum making things easier to spot. usually other bodily fluids like semen, saliva, they are naturally luminecent.
So not complete bullshit but not exactly true either from what i gathered, but hey it's fiction