Casandra "Cassie" Ventura is taking the stand in Sean "Diddy" Combs' criminal trial, almost two years after she sued her ex-boyfriend.

Follow the latest from Sean "Diddy" Combs' sex trafficking trial in N.Y. as Cassie Ventura testifies against the artist for the second day in a row.

As Sean "Diddy" Combs' trial unfolds in NYC, here's what to know about Cassie Ventura and other the key witnesses in the case.