Criminal Intent

A criminal mastermind.. the Mob.. people going missing at an alarming rate. Eva is a crime writer, passing on her experience and tips to would-be new writers, but she was witness to an awful crime and is awaiting the trial to give evidence. On the run suddenly, nearer to the trial, her students are also appearing to be targeted. How can she keep them safe and herself too Is this still the Mob or is this a new set of criminals on the loose? An undercover cop is tasked to check on Eva. Just to ensure that she hasn't got something to do with it too...
So is she being targeted just by the Mob, as this is the trial she's giving evidence for.. and why do the police think she has something to do with the recent disappearances? Will the undercover cop come clean and keep her away from the criminals setting up to catch her out... and possible make her disappear too..