The key answer of exercise 12

a)

1. thug: a violent person who may attack people
2. Art thieves are
3. Thuggish is the adjective used to describe a person or person's behaviour; thuggery is the noun used to describe violent behaviour.
4. Look at the phonemic transcription for a guide as to how the word is pronounced.

b)

1. aesthetes → a person who knows about / appreciates beautiful art objects, like paintings, sculpture, etc.
2. mastermind → to organise a complicated plan
3. hideout → a place where you can hide
4. track down → find, after searching for a long time
5. stuffed → push something roughly into a small space
6. crack a case → solve a case (informal)
7. haul → amount of things that have been stolen