I had a case in court and a witness lied about me. What can I do about it? Can I sue him?
Practically speaking, there is little you can do. The chances that a district attorney will prosecute the witness for perjury are almost zero. You cannot sue someone for statements – even untrue statements – made while testifying in court, even if the statements would have constituted slander if they were said out of court. Witnesses who testify in court are protected from slander lawsuits by what is known as the "litigation privilege."