Information can be found in such sources as police records and memoranda, autopsy reports, results of laboratory tests, and other physical evidence such as the clothing of a victim or suspect involved in violent crime. A defendant has an absolute right to examine these investigative and scientific reports upon which government witnesses will rely to refresh their recollection at trial. Defense counsel should make a demand motion to the trial court for an order requiring the prosecutor to disclose all evidence before the trial, since it may contain inconsistencies, improper and incorrect conclusions, and exculpatory evidence. Access to such reports is essential to the cross-examination of a firearms expert. One serious problem that has confronted the defense bar is the extent to which the government must preserve firearms evidence for discovery and inspection. When such evidence is destroyed, defense counsel should make a motion to dismiss a criminal case, based upon the denial of the constitutional right to confrontation. Another problem is the government's failure to disclose exculpatory evidence in its possession or under its control. Since such evidence does not have to be disclosed by the prosecution unless proper demand has been made, defense counsel should routinely make formal demand for the disclosure of exculpatory evidence prior to trial. Many prosecutors have an 'open file' policy whereby the defense has access to the prosecutors' entire file in a criminal case, including physical evidence and the results of scientific tests completed by firearms witnesses. However, such a policy can be a trap for the defense counsel if the prosecutor does not have all the evidence. Therefore, it is important for the defense to demand exculpatory evidence within the possession or under control of the prosecutor. A total of 31 references are included. For related articles, see NCJ 75559 and 75561-62.