Oh, since I utilized this earlier today, here's a quick and easy (and messy) way to make bloody smeared hand prints without going through the trouble to slaughter someone. First, though, you'll wanna make sure you have some really good hand cleaner. Fast Orange, GoJo, Lava soap, Masters' Hand Soap, really heavy-duty stuff. You'll need it.
Anywho, get out some butcher paper (or freezer paper, or just a big sheet of white paper) and lay it flat. Get some red food dye and put a drop on the tip of each finger and the heel of your hand, then rub your hands together to get both palms evenly coated.
Slap your hands down on the paper, then drag them to one side. Repeat if desired.
Immediately wash your hands using the aforementioned cleaner so that your skin isn't stained red.
Tape up your newly-made crime scene.