Why Diddy trial witness Capricorn Clark is key to his racketeering and sex-trafficking charges

Sean "Diddy" Combs, pictured in 2010, is due to hear testimony by his former personal assistant and marketing executive, Capricorn Clark, right, on Tuesday at his Manhattan sex-trafficking and racketeering trial.

Gus Ruelas/Reuters, left; US Attorney's Office, Southern District of New York, right.

• A third former employee of Sean "Diddy" Combs may testify against him in Manhattan on Tuesday.
• Capricorn Clark is a onetime personal assistant who rose to be one of his top marketing executives.