The Big Sleep and The Long Goodbye

At what point do we describe someone to be insane? Is it more difficult to be able to notice a difference between a sane person and someone who has completely lost it, when dealing with people of respected or classified stature. What makes a sane person is a person who wouldn't do certain things that a insane person would do. Is taking the law into your own hands insane. Yes of course it is. If you aren't insane you are guilty of a crime. Normal people abide by the law and fit in some how. Is bending the law insane? When you have the right to carry a gun and hold people accountable for certain illegal actions, you have a lot of responsibility. When you have the opportunity to put someone in cuffs and have him sent on his way to trial; as a officer of the law, is it justice to commit to extreme measures of punishment in reaction to what someone has did or done? Take Mr. Marlowe in The Big Sleep killing Canino and Marlowe in The Long Goodbye killing the man who confessed to smashing the woman's face in. Both of them are private detectives who have shot someone who they could've brought in to be tried. As rough as this may seem or as much as those killed may have deserved to die; when does the law give its power to individuals or is that question already answered? If this is the case where is hope for those falsely accused? Roger Wade from the Long Goodbye commits suicide after his issues with the hospital. I think he was driven to suicide which could've been from being falsely accused after some displays of irrational behavior caused by those pushing him over the edge.