I would fluff up the details -- like, maybe the female accomplice has access to digitalis, or knows how to distill it from Foxglove plants (adds a nice, earthy touch, don't ya think?), and gives it to the male accomplice to inject into the victim in order to bring on a heart attack. Maybe the victim fights back, and the male accomplice has to knock her out before injecting the drug.
I need to quit watching CSI.
"Greta: Dr. Baden, a potassium imbalance... lets first talk about... if you had a potassium deficiency, can that cause the condition that Terri Schiavo had?
Dr.Baden: Umm, CAN, but UNLIKELY.
Dr.Baden: Potassium is very interesting , its probably the most lethal poison we have when it is injected rapidly, and thats why its the poison that kills people in capital punisment by lethal injection.
Dr.Baden: And it stops the heart from beating properly. Too much of it. But also, too little of it, hypo-potassium, can also cause the heart to stop beating properly, and lead to lack of blood flow to the brain, and death of brain cells by lack of oxygen.
Greta: All right, would it, would it...
Dr.Baden: But thats very unusual Greta, extremely unusual.
Greta: A normal healthy woman, ahh, I assume would have no reason for instance, to take potassium supplements unless perhaps she was on a dieuretic, or had some other medication that would cause a potassium depetion. Is that right?
Dr.Baden: That is correct.
Greta: All right. Um, is there any explanation in your mind, and I realize you were not her treating physician, but why would a woman her age have a potassium, umm, imbalance?
Dr.Baden: Extremely unlikely..., unless she had certain kinds of diseases, which she doesn't have. She was in her 20's... the reason she is in the state she is in is because there was a period of time, maybe 5 minutes or 8 minutes when not enough oxygen was going to her brain. That can happen when the heart stops for 5 or 8 minutes, but she had a healthy heart from what we can see.