Who is the killer

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Across
  1. 3. you use this to wash your hair
  2. 4. 365 days
  3. 6. Dalí was a famous Spanish...
  4. 8. the opposite of finish
Down
  1. 1. the Joker's worst enemy
  2. 2. the name of your English book
  3. 5. if you are not wrong, you are ...
  4. 7. if you are not confident, you are ...
  5. 8. the opposite of front