i like the contrast between the first 2 and the last one.
some suggestions on shading:
very good sense of values, first of all.
don't make your outlines so dark if you're planning on using value to define form.
practice using longer pencil strokes.
consider using a graphite stick for shading large areas.
watch out for strange value areas like you have in the second picture, underneath the victim's face.
in the dress, consider using pencil strokes more perpendicular to the outline/boundary of a fold.
avoid perpendicular cross-hatching (in her arm).
The first sketch is pretty good, that's a difficult angle to draw from.
your bodies are strong, the chick's face isnt as strong, . you should probably try to foucus on chicks' faces for a bit and get them stronger, though women dont have as much structure, try to think of thier faces in 3 dimensions. rather than on the individual details of the face. I sometimes have similar problems
Other than that looks pretty strong.
i'll work on the things that were suggested
I don't have any further crits to add. I just wanted to say that I liked the drawings and I think you have talent.