I recently saw a tv show - or maybe a movie on tv. I'm not sure what it was, and I only saw the end, but this is what I gathered:

There was some sort of spirit, and only certain people could see/hear him. One was a teenage boy; the other was a female detective. The spirit was helping the detective solve some cases by showing her visions. He was also preventing crime using the teenage boy.

You see, the spirit knew in advance when someone was planning a mass murder. A fed-up nurse planning to lethally inject some patients. A man planning to shoot up a diner. Some of these people were also planning to commit suicide after. Some weren't.

The spirit taught the boy how to commit a crime and leave no evidence. He got the boy to hold a gun to people's heads and make them write suicide notes, then commit suicide. So, to save the lives of many, the boy was killing those plotting to kill.

The detective found out about it and thought it was wrong. I felt torn. If you knew for sure that someone was going to kill many others, would it be wrong to take that person's life?

And then the detective was going to arrest the boy and stop this vigilante mission. So the spirit told the boy to kill her. On the one hand, it seemed obviously wrong. She wasn't going to kill anyone. But on the other hand, her actions would prevent them from saving the lives of many.

I was talking about this to a co-worker and we came up with some other moral gray areas we've seen on tv or read in books:

- A woman who has tried everything to escape a stalker (who the police would do nothing about) kills him and leaves no evidence. They only know it's her because she took a CSI class with one of their detectives. So one of the CSIs tells her that the evidence is circumstantial and they won't convict her if she doesn't admit it. Was he wrong to say that? What else could she have done to free herself of this stalker?

- A man whose daughter has been killed believes he knows who did it. CSI does too, but the suspect won't let them in his house and they don't have enough for a warrant. So the father steals a John Doe from the hospital morgue and shoves it down the guy's chimney. The house becomes a crime scene, and CSI has access. They end up finding the girl's body as well. Was his theft of a body justified?

- A girl whose sister was raped is upset when the rapist is acquitted. So she gets a job in his office, plants evidence at his desk and in her house, and says he raped her. Is she wrong to accuse him of something he didn't do, because she knows he did it to someone else? The justice system said yes - when she was caught in her lie, she was sent to prison for perjury.

What do you think? When is a crime justified? How can you know what to do in these gray situations?