A certain crime is punishable if attempted but not punishable if committed. What is it?

Answer: Suicide.

More Riddles for Adults with answers

More Riddles for Adults

A headless man had a letter to write; It was read by a man who had lost his sight. The dumb repeated it word for word, And deaf was he who listened and heard. What is it?
A man is discovered dead sitting at his desk, alone in the locked office. He did not commit suicide and there was no weapons in the room. The only clue is a sealed envelope on the desk in front of him. How did he die?
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I am a box that holds keys without locks, yet they can unlock your soul. What am I?
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I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody. What am I?
I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business. What am I?
I like to be blue and have been since '63, but I could be anything if my circuit was fixed. I'm small yet infinitely bigger. I was grown but I'm made of metal. I am the last of my kind just like my beautiful idiot once was. Together we will travel, have traveled or are traveling. Tenses as seen, seeing, will see, are mysterious to me. Wibblies and wobblies, time correctly described by a Lord. What will I be, what have I been, or is it, what am I?
I weaken all men for hours each day. I show you strange visions while you are away. I take you by night, by day take you back, None suffer to have me, but do from my lack. What am I?
If you can buy 1 for $1, 14 for $2, and 145 for $3, what are you buying?
My life is often a volume of grief, your help is needed to turn a new leaf. Stiff is my spine and my body is pale, but I'm always ready to tell a tale. What am I?