One of the most frequent questions put to criminal defense lawyers is, if you know (somehow) that your client is guilty, how can you represent him/her. To most lawyers, that question is easily answered by saying everyone is entitled to representation in this country. Or the response is that while the client may be guilty of something, he may not be guilty of the more serious charge levied. For example, the client may be guilty of murder in the second degree which requires proof of intent, but not first degree murder which generally requires intent plus premeditation. A variation of the question might be, if you know your client is guilty of a particular offense, can you ethically permit him to testify under oath that he did not commit the act? The answer is no, a lawyer cannot suborn perjury. Some lawyers simply choose not to find out from the client whether he is guilty or not- they don’t ask.
A related issue is whether a lawyer must disclose unfavorable evidence to the prosecutor discovered during the defense investigation of the case. I am familiar with a murder case where the defendant was charged with murder in the first degree and attempted murder. Briefly, the state claimed that he had shot the victim in the head and shot at the victim’s girlfriend all from ½ block away. The girlfriend testified to this. Although the medical examiner found gun-powder in the stippling around the entry of the head wound, (The powder particles were not burned), she testified that this could be consistent with a shooting from a ½ block away. The defense expert, who was a nationally renowned expert (who had worked on the John F. Kennedy and Martin L. King autopsies), put the maximum distance between the muzzle of the gun and entrance wound at roughly 8 inches. In other words, it was clear that unburned particles couldn’t have travelled ½ block- the shot had to have come from close range. During the investigation of the case, the defense investigator located the owner of a vehicle which had been parked on the avenue where the shooting took place; the police had failed to discover this witness. When questioned as to whether he had any knowledge of the shooting, he hadn’t seen anything but his car had a bullet hole in the passenger door; the car would have been parked near to the spot where the victim and girlfriend were standing. Moreover, the angle of the gunshot hole matched the girlfriend’s distance testimony. The lawyer in that case was informed that he did not have to disclose this information to the prosecutor. Ultimately the defendant was acquitted.
The case is mentioned to illustrate the dual duties a lawyer has to the court and his client; he cannot allow his client to lie but he can’t do anything to harm his client either. Of course, there may be exceptions and special rules applicable in certain cases but this was a general rule pertaining to this case.