Actions by school staff before Michigan shooting fuel questions about their liability

In the aftermath of last week's deadly shooting at a Michigan high school, prosecutors took the rare step of bringing criminal charges against the parents of the suspect.

And they have not ruled out what would be an even more extraordinary step: a case against the school itself.

The prospect of legal action against Oxford High School, located on the edge of suburban Detroit, comes as details continue to surface about the concerns raised by school staff in the hours before the shooting that left four students dead and six others wounded, along with a teacher.

Those concerns culminated in a meeting of guidance counselors, the suspect and his parents on the morning of the attack, after which he was allowed to return to class.

Now, questions have mounted about whether school officials could have taken additional steps to prevent the shooting and whether the school or its employees could be facing civil or even criminal liability as a result.

Speculation has been driven,