### Clue: Names criminal methods used by thieves (9)
### Answer: MONICKERS 
 ### Explanation: Definition: Names
  MO(abbrev. for "modus opeandi",Latin for mode,method of operating, criminal or otherwise) **plus** (used by) NICKERS(people who steal,nick,thieves).  Nice misdirection by "criminal", often used as an anagrind. 
Answer: Slang for persons' names, especially nicknames or aliases.