An attorney is bound to adhere to the Rules of Professional Conduct. The Oklahoma Rules of Professional Conduct may be found here http://www.oscn.net/applications/oscn/index.asp?ftdb=STOKRUPR&level=1
Rule 3.3 governing "Candor Toward The Tribunal" states:
(a) A lawyer shall not knowingly:
(1) make a false statement of fact or law to a tribunal or fail to correct a false statement of material fact or law previously made to the tribunal by the lawyer;
(2) fail to disclose to the tribunal legal authority in the controlling jurisdiction known to the lawyer to be directly adverse to the position of the client and not disclosed by opposing counsel; or
(3) offer evidence that the lawyer knows to be false. If a lawyer, the lawyer’s client, or a witness called by the lawyer, has offered material evidence and the lawyer comes to know of its falsity, the lawyer shall take reasonable remedial measures, including, if necessary, disclosure to the tribunal. A lawyer may refuse to offer evidence that the lawyer reasonably believes is false.
(4) fail to disclose a fact to a tribunal when disclosure is necessary to avoid assisting a criminal or fraudulent act by the client.
(b)A lawyer who represents a client in an adjudicative proceeding and who knows that a person intends to engage, is engaging or has engaged in criminal or fraudulent conduct related to the proceeding shall take reasonable remedial measures, including, if necessary, disclosure to the tribunal.
(c) The duties stated in paragraphs (a) and (b) continue to the conclusion of the proceeding, and apply even if compliance requires disclosure of information otherwise protected by Rule 1.6.
(d) In an ex parte proceeding, a lawyer shall inform the tribunal of all material facts known to the lawyer which will enable the tribunal to make an informed decision, whether or not the facts are adverse.
Rule 3.3 seems to be particularly applicable to your case.
In addition, Rule 3.8 contains Special Responsibilities of Prosecutors.
Rule 8.4 governs Misconduct and states in part:
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; . . .
I believe the expression that it is the prosecutor's duty to seek justice and not just convictions derives from these rules that govern attorney conduct.