Awareness of the existence of a criminal record, which is peculiarly within the knowledge of law enforcement, is imputable to the trial prosecutor notwithstanding a lack of actual knowledge. Kyles v. Whitley, 514 U.S. 419, 437-38, 115 S. Ct. 1555, 1567-68, 131 L. Ed. 2d 490, 508 (1995) (trial prosecutor has a duty to learn of any evidence favorable to defendant known to others acting on government's behalf); State v. Nelson, 155 N.J. 487, 498-500, 715 A.2d 281 (1998), cert. denied, 525 U.S. 1114, 119 S. Ct. 890, 142 L. Ed. 2d 788 (1999) (lack of actual awareness by trial prosecutor does not relieve the State of its Brady obligations). The Brady disclosure rule (Brady v. Maryland, 373 U.S. 83, 83 S. Ct. 1194, 10 L. Ed. 2d 215 (1963)) applies to information of which the prosecution is actually or constructively aware. However, cross-examination is routinely regarded as the most effective means of challenging the credibility of a witness and thereby discovering the truth. State v. Silva, 131 N.J. 438, 444, 621 A.2d 17 (1993). One of the tools available to the cross-examiner in attempting to impeach the credibility of a witness is the witness' prior conviction of a crime. N.J.R.E. 609.