Source : http://www.in.gov/judiciary/rules/prof_conduct/index.html#_Toc313019228
Rule 8.3. Reporting Professional Misconduct
(a) A lawyer who knows that another lawyer has committed a violation of the Rules of Professional Conduct that raises a substantial question as to that lawyer’s honesty, trustworthiness or fitness as a lawyer in other respects, shall inform the appropriate professional authority.
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Comment
[1] Self-regulation of the legal profession requires that members of the profession initiate disciplinary investigation when they know of a violation of the Rules of Professional Conduct. Lawyers have a similar obligation with respect to judicial misconduct. An apparently isolated violation may indicate a pattern of misconduct that only a disciplinary investigation can uncover. Reporting a violation is especially important where the victim is unlikely to discover the offense.
[3] If a lawyer were obliged to report every violation of the Rules, the failure to report any violation would itself be a professional offense. Such a requirement existed in many jurisdictions but proved to be unenforceable. This Rule limits the reporting obligation to those offenses that a self-regulating profession must vigorously endeavor to prevent. A measure of judgment is, therefore, required in complying with the provisions of this Rule. The term “substantial” refers to the seriousness of the possible offense and not the quantum of evidence of which the lawyer is aware. A report should be made to the bar disciplinary agency unless some other agency, such as a peer review agency, is more appropriate in the circumstances. Similar considerations apply to the reporting of judicial misconduct.
Rule 8.4. Misconduct

It is professional misconduct for a lawyer to:
(a) violate or attempt to violate the Rules of Professional Conduct, knowingly assist or induce another to do so, or do so through the acts of another;
(b) commit a criminal act that reflects adversely on the lawyer’s honesty, trustworthiness or fitness as a lawyer in other respects;
(c) engage in conduct involving dishonesty, fraud, deceit or misrepresentation;
(d) engage in conduct that is prejudicial to the administration of justice;
(e) state or imply an ability to influence improperly a government agency or official or to achieve results by means that violate the Rules of Professional Conduct or other law;
(f) knowingly assist a judge or judicial officer in conduct that is a violation of applicable rules of judicial conduct or other law; or
Comment
[1] Lawyers are subject to discipline when they violate or attempt to violate the Rules of Professional Conduct, knowingly assist or induce another to do so or do so through the acts of another, as when they request or instruct an agent to do so on the lawyer’s behalf. Paragraph (a), however, does not prohibit a lawyer from advising a client concerning action the client is legally entitled to take.
[2] Many kinds of illegal conduct reflect adversely on fitness to practice law, such as offenses involving fraud and the offense of willful failure to file an income tax return. However, some kinds of offenses carry no such implication. Traditionally, the distinction was drawn in terms of offenses involving “moral turpitude.” That concept can be construed to include offenses concerning some matters of personal morality, such as adultery and comparable offenses, that have no specific connection to fitness for the practice of law. Although a lawyer is personally answerable to the entire criminal law, a lawyer should be professionally answerable only for offenses that indicate lack of those characteristics relevant to law practice. Offenses involving violence, dishonesty, breach of trust, or serious interference with the administration of justice are in that category. A pattern of repeated offenses, even ones of minor significance when considered separately, can indicate indifference to legal obligation.
[3] A lawyer may refuse to comply with an obligation imposed by law upon a good faith belief that no valid obligation exists. The provisions of Rule 1.2(d) concerning a good faith challenge to the validity, scope, meaning or application of the law apply to challenges of legal regulation of the practice of law.
All lawyers who just read the above in blue and know something about any illegal conduct of attorney in a law firm probably do not have the ground for a good faith defense. Time to rat out your peers.