WITH THE INCREASING VOLUME OF EVIDENCE BEING KEPT IN PROPERTY ROOMS OF POLICE DEPARTMENTS, IT IS IMPRACTICAL TO INSPECT ALL EVIDENCE PERIODICALLY. A RANDOM SAMPLE OF EVIDENCE, HOWEVER, SHOULD BE EXAMINED AT REGULAR INTERVALS. TO BE SECURE, AN EVIDENCE SYSTEM SHOULD BE CLOSED, WHEREIN ALL PROPERTY IS ASSIGNED AN IRREVOCABLE NUMBER, FULLY DOCUMENTED, AND SEALED. SPECIFIC PREREQUISITES OF A CLOSED SYSTEM ARE AS FOLLOWS: (1) UNIFIED, COORDINATED, AND DEPARTMENTWIDE PROPERTY SECURITY SYSTEM; (2) POLICY INDICATING THAT ALL PROPERTY (PROPERTY FOUND, PROCEEDS OF A CRIME, AND CRIMINAL EVIDENCE) COMING INTO THE POSSESSION OF DEPARTMENT MEMBERS FROM ANY SOURCE MUST BE RELINQUISHED TO A PROPERTY CLERK WITHIN A REASONABLE TIME PERIOD; (3) ADMINISTRATIVE POLICY REGARDING THE HANDLING OF CRIMINAL EVIDENCE BY A SECURITY SYSTEM OUTSIDE THE DEPARTMENT; (4) INDENTIFICATION AND DOCUMENTATION OF NARCOTICS EVIDENCE UPON SEIZURE; AND (5) DEPARTMENT POLICY INDICATING THAT AN INTERNAL RANDOM MONITORING SYSTEM BE FULLY OPERATIONAL, WITH SPECIFIC AND FREQUENT MONITORING OF HIGH-PRIORITY EVIDENCE. QUALITY CONTROL FOR THE DETECTION OF HUMAN ERROR OR NEGLIGENCE IS ESSENTIAL IN EVIDENCE SECURITY, AND FULL-SCALE INVESTIGATIONS SHOULD BE INSTITUTED IF ANY DEVIATIONS ARE FOUND BETWEEN INITIAL AND SUBSEQUENT ANALYSIS REPORTS. EVEN AFTER EVIDENCE HAS BEEN USED IN COURT, IT MUST BE KEPT SECURE PRIOR TO DISPOSAL IN ORDER TO PREVENT ITS THEFT AND SALE. IT IS RECOGNIZED THAT, IN PERFORMING ROUTINE SAMPLING OF PRIORITY EVIDENCE, ONE IS WORKING WITH THE SCIENCE OF PROBABILITIES AND THAT THERE CAN BE FAILURES IN ANY EVIDENCE SECURITY PROCEDURES. FOOTNOTES ARE PROVIDED. (DEP)