Massachusetts Rules of Professional Conduct Rule 3.4: Fairness to Opposing Party and Counsel
(a) unlawfully obstruct another party's access to evidence or unlawfully alter, destroy, or conceal a document or other material having potential evidentiary value. A lawyer shall not counsel or assist another person to do any such act;
(b) falsify evidence, counsel or assist a witness to testify falsely, or offer an inducement to a witness that is prohibited by law;
(d) in pretrial procedure, make a frivolous discovery request or fail to make reasonably diligent effort to comply with a legally proper discovery request by an opposing party;
(e) in trial, allude to any matter that the lawyer does not reasonably believe is relevant or that will not be supported by admissible evidence, assert personal knowledge of facts in issue except when testifying as a witness, or state a personal opinion as to the justness of a cause, the credibility of a witness, the culpability of a civil litigant, or the guilt or innocence of an accused;
(1) the person is a relative or an employee or other agent of a client; and
(2) the lawyer reasonably believes that the person's interests will not be adversely affected by refraining from giving such information;
(g) pay, offer to pay, or acquiesce in the payment of compensation to a witness contingent upon the content of his or her testimony or the outcome of the case. But a lawyer may advance, guarantee, or acquiesce in the payment of:
(1) expenses reasonably incurred by a witness in attending or testifying
(2) reasonable compensation to a witness for loss of time in attending or testifying
(3) a reasonable fee for the professional services of an expert witness;
(h) present, participate in presenting, or threaten to present criminal or disciplinary charges solely to obtain an advantage in a private civil matter; or
(i) in appearing in a professional capacity before a tribunal, engage in conduct manifesting bias or prejudice based on race, sex, religion, national origin, disability, age, or sexual orientation against a party, witness, counsel, or other person. This paragraph does not preclude legitimate advocacy when race, sex, religion, national origin, disability, age, or sexual orientation, or another similar factor is an issue in the proceeding.
Adopted June 9, 1997, effective January 1, 1998.
 The procedure of the adversary system contemplates that the evidence in a case is to be marshalled competitively by the contending parties. Fair competition in the adversary system is secured by prohibitions against destruction or concealment of evidence, improperly influencing witnesses, obstructive tactics in discovery procedure, and the like.
 Documents and other items of evidence are often essential to establish a claim or defense. Subject to evidentiary privileges, the right of an opposing party, including the government, to obtain evidence through discovery or subpoena is an important procedural right. The exercise of that right can be frustrated if relevant material is altered, concealed or destroyed. Applicable law in many jurisdictions makes it an offense to destroy material for purpose of impairing its availability in a pending proceeding or one whose commencement can be foreseen. Falsifying evidence is also generally a criminal offense. Paragraph (a) applies to evidentiary material generally, including computerized information.
 With regard to paragraph (b), it is not improper to pay a witness's expenses or to compensate an expert witness on terms permitted by law.
 Paragraph (f) permits a lawyer to advise employees of a client to refrain from giving information to another party, for the employees may identify their interests with those of the client. See also Rule 4.2.
 Paragraph (g) carries over the provision of former DR 7-109(C) concerning the payment of funds to a witness. Compensation of a witness may not be based on the content of the witness's testimony or the result in the proceeding. A lawyer may pay a witness reasonable compensation for time lost and for expenses reasonably incurred in attending the proceeding. A lawyer may pay a reasonable fee for the professional services of an expert witness.
 Paragraph (h) is taken from former DR 7-105(A), but it prohibits filing or threatening to file disciplinary charges as well as criminal charges solely to obtain an advantage in a private civil matter. The word "private" has been added to make clear that a government lawyer may pursue criminal or civil enforcement, or both criminal and civil enforcement, remedies available to the government. This rule is never violated by a report under Rule 8.3 made in good faith because the report would not be made "solely" to gain an advantage in a civil matter.
 Paragraph (i) is taken from former DR 7-106(C)(8) concerning conduct before a tribunal that manifests bias or prejudice based on race, sex, religion, national origin, disability, age, or sexual orientation of any person. When these factors are an issue in a proceeding, paragraph (i) does not bar legitimate advocacy.
Corresponding ABA Model Rule. Identical to Model Rule 3.4(a), (b), (c), (d), (e), and (f); (g) from DR 7-109 (C), (h) from DR 7-105, and (i) from DR 7-106 (C)(8) are new.
Corresponding Former Massachusetts Rule. DR 7-102 (A)(6); DR 7-105; DR 7- 106 (A) and (C), DR 7-109, S.J.C. Rule 3:08 PF 4, DF 9; See also DR 7-103 (B), DR 7-104 (A)(2).