You have been asked by the senior partner in your law firm to prepare a brief memorandum (2-4 pages) for the lawyers in your firm as to how to avoid ethical problems when preparing for and handling criminal defense litigation. Think carefully about the ethical issues which may arise in such litigation once the client has agreed to representation, and in particular situations where (a) you have been asked by the client to present an alibi witness who may be lying, (b) you know your client will not tell the truth when she takes the stand, and (c) your client promised to tell the truth but then lied on the stand. Include your suggestions as to the appropriate conduct necessary to avoid the problems. Focus on the direction given in the relevant rules, Comments, and materials in your text, including Supreme Court cases.