After finding a key piece of evidence showing that there was misconduct in Derek Thompson's trial Detective Carisi asks Bayard Ellis if he thinks it is sufficient evidence for Senior ADA O'Dwyer to drop the charges, which he could not do even if he wanted to. A prosecutor only has discretion to drop pending charges against a person; once a person has been found guilty of charges at trial the DA's office no longer has any say, after that the charges can only be dismissed if a judge from a higher court finds sufficient cause to vacate the verdict due to a miscarriage of justice.