Sort of, blood spatter is kinda legit: It’s derived from old tracking techniques so it’s not totally bullshit (but it’s also not a super power or anything). You can tell if someone was running and blood was dripping or if it came from them getting repeatedly hit with something, etc. That’s part of forensics, some of which is legit science (though it’s not perfect and there are people who are full of shit that hire themselves out as “experts” sometimes).