On June 17, 2010, effective July 1, 2010, the Colorado Supreme Court, following the lead of the American Bar Association, unanimously adopted new ethics rules for prosecutors pertaining to criminal defendants who may have been wrongfully convicted.
There is a now a duty to disclose new evidence to a convicted defendant and ask the court to appoint counsel for unrepresented defendants, within "a reasonable time," if "a prosecutor knows of new, credible and material evidence creating reasonable probability that a convicted defendant did not commit an offense of which the defendant was convicted." Colorado Rule of Professional Responsibility 8.3(g).
Evidence is new, whether or not it was known to the prosecutor at the time of the trial if it was not disclosed for any reason, legitimate or otherwise, to the defense.
According to the official comment to the rule determination of a "reasonable time" include "whether the defendant is subject to the death penalty, is presently incarcerated, or is under court supervision" as well as the availability of investigators, the original prosecutor, what further investigation is appropriate, and "prejudice to an ongoing investigation."
Furthermore, if "a prosecutor knows of clear and convincing evidence establishing that a defendant was convicted . . . of an offense that the defendant did not commit" in his or her jurisdiction, "the prosecutor shall take steps in the appropriate court, consistent wit applicable law, to set aside the conviction."
Prosecutors do not violate either rule if they make a "reasonable judgment in good faith" that the evidence is not covered by the rule, even if the determination is later determined to be wrong. The rule will not necessarily apply where the defendant pleaded guilty in a way that waived the establishment of a factual basis for the plea.
Source: Colorado Supreme Court, Rule Change 2010(13).
Prosecutors who violate these rules of professional conduct can be sanctioned with punishments from a private reprimand to suspension to the lawyer's license to practice law to disbarment, depending upon the facts and circumstances of the case.
The Attorney Regulatory Counsel in Colorado, a full time attorney ethics prosecutor who reports to the Colorado Supreme Court, is charged with enforcing the rule, something that generally happens on the basis of citizen complaints, including complaints from fellow lawyers who (in theory, at least) have a duty to report ethical violations of which they are aware.
Prosecutors have always had a long standing duty, stronger than the usual duty of lawyers not to bring frivolous and groundless lawsuits, not to prosecute people for offenses when there is no probable cause to believe have committed a crime. This requirement is almost irrelevant in practice, however, because a conviction is generally viewed as conclusive proof that probable cause existed to prosecute a crime, and in serious felony cases either a grand jury or probable cause hearing judicially screen cases to determine if probable cause exists.
Prosecutors also have a constitutional duty that was clearly only much more recently (it was part of the Warren court constitutionalization of criminal procedure), to disclose exculpatory evidence to criminal defendants in the trial process. Breach of this ethical duty of prosecutors is a ground for sanctioning the prosecutor and for setting aside the conviction. Claims that exculpatory evidence was not disclosed make up a large share of all attempts to set aside allegedly wrongful convictions, and a larger share of successful attempts to do so and of successful attempts to impose professional discipline on prosecutors.
The empirical evidence shows that while there are wrongful convictions in cases where no criminal justice official actually engaged in misconduct, that a large share of all wrongful convictions are attended by misconduct by law enforcement and/or prosecutors.
The duty is notable because it is an exception to the general rule that lawyers are one sides advocates. It exists because legally: "A prosecutor has the responsibility of a minister of justice and not simply that of an advocate."
The new rule goes beyond the old standard because does not permit a prosecutor to simply remain subjective pure during the course of a prosecution and then wash his or her hands of the case once a conviction is obtained and entered by an official court pronouncement, and then let sleeping dogs lie if new evidence is discovered or there was past misconduct by a prosecutor.
Since prosecutors have ongoing interactions with law enforcement, working with them in essentially every single criminal case that is prosecuted, but are bureaucratically distinct and much less likely to plan on being prosecutors their entire lives (a large share of prosecutors get the job right out of law school, spend several years trying cases, and then leave to jobs as litigator of some sort in the private sector), prosecutors are often in a position to gain exculpatory information about a case after a conviction is obtained, and to have a certain amount of independence from law enforcement that fellow officers who are in the same bureaucratic entity and usually planning on spending a lifetime in that career, do.
The threat that a rule of professional conduct violation can pose to a lawyers entire career gives prosecutors an incentive to overcome the embarassment and institutional disinclination to admit to having been wrong or to having done something wrong in the past, out of fear that someone else will learn of the lapse and report it.
This follows the large development of criminal procedure post-Gideon that sees the criminal justice process as something other than a purely adversarial process. Prosecutors have a duty to not try to prosecute innocent people, and now to make it possible for innocent people to exonerate themselves, and defendants are entitled (in theory anyway) to "effective assistance of counsel" in the form of a public defendant or privately retained counsel.
Ineffective assistance of counsel claims by criminal defendants are often brought but rarely prevail in collateral review of criminal convictions. But, evidence of non-disclosure of exculpatory evidence by prosecutors often does provide a successful claim for relief.
Non-disclosure of exculpatory evidence is also critical because it provides a procedural hook by which a court reviewing a conviction can consider the merits of whether a defendant was in fact guilty or innocent, rather than merely considering purely procedural issues from the trial record itself. Bare claims of actual innocence almost never suffice to challenge a conviction, because if the jury considered the evidence, or the defense counsel was aware of it and didn't present it to a jury, the original trial presumably resolve the question of whether or not the defendant was guilty or innocent on the merits. But, when new exculpatory evidence is revealed, that allows a court collaterally reviewing a conviction to consider not only the new evidence in isolation, but also to consider the old evidence in light of the new exculpatory evidence.
Thus, new exculpatory evidence in addition to considering the new facts, provides a means by which mistakes in evaluating the evidence by the original trial jury can be revisited.
The new ethical rule also gives groups like the Innocence Project, when they are aware that there might be exculpatory evidence out there, much more leverage to obtain cooperation from prosecutors in their efforts.