Logic riddles

A man entered his house and was about to hang up his coat when he heard his wife shout; "No John! Don’t do it!" There was a shot and he could hear his wife fall down. When he entered the kitchen he saw his wife and the gun lying on the floor. There was a police officer, a doctor, and a lawyer standing next to her. Peter immediately knew that the police officer had shot her. But how did he come to know?

What is as light as a feather but impossible to hold for several minutes?

I have a bed but I do not sleep. I have a mouth but I don't eat. You hear me whisper, but I never talk. You can see me run, yet I never walk. What am I?

When you put this in a heavy wooden box, the box will become lighter.

Two men are in a desert. They're both wearing backpacks. One of the men is dead. The man who is alive, has his pack open. The dead man's pack is closed. What is in their packs?

You leave home, make three left turns, and return home where you find two men wearing masks. Who are they?

During what month do people sleep the least?

If an electric train is going east at 60 miles an hour and there is a strong westerly wind, which way does the smoke from the train drift?

A boy fell off a 30 meter ladder but did not get hurt. Why not?

You can easily touch me, but not see me. You can throw me out, but not away. What am I?