hmmm blood. i can't think of any blood either. there is that surreal image of blood that fills the screen when columbo is describing the death of her husband to leslie williams. but no, i can't think of any blood on the actual victims.
There was some blood on Vera Miles's fingertips when she touches the broken glass from the slide...but I don't know if that really counts because it was her blood, not the victim's.
We also see the bloody bullet hole in the head of the victim in "Dead Weight."
There is also blood in "Agenda For Murder." Frank Staplin's blood spot that 'dried' underneath the gun. That brings up an odd point. How long did it take the blood to dry? Finch put the gun on top of it almost immediately after the shooting if I recall correctly...