noun (n)

• a thief who grabs and runs(noun.person)

  Example:
  A purse snatcher.
  

  source: wordnet30
• someone who unlawfully seizes and detains a victim (usually for ransom)(noun.person)

  Synonym:
  abductor, kidnaper, kidnapper
  

  source: wordnet30
• One who snatches, or takes abruptly.(noun)

  source: webster1913