The 0.5-Gram Gap
On a Tuesday at 0640, military police stop a civilian employee's vehicle at a gate for a broken taillight. A K-9 alerts; MPs find a knotted plastic bag under the passenger seat containing a white powder. Field test is positive for cocaine; the field scale reads 12.4 grams gross. CID Agent K. arrives at 0720, photographs the bag, places it in a heat-sealed evidence bag, writes the case number and her initials on the bag, and logs it in the MP evidence locker at 0815. The locker is full, so the MP desk sergeant puts the bag in an open cardboard box in the shift office until the CID evidence custodian arrives at 0900. At 0905, the custodian receives the bag, notes the seal is intact, and issues a DA Form 4137. The lab later reports 11.9 grams net, seal intact, but notes the bag was not heat-sealed on one corner and had been folded. Defense counsel has requested the chain of custody and the field test kit.
1. Identify the chain-of-custody weaknesses and explain whether they make the evidence inadmissible.
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The weak points are the 45-minute gap in an unsecured shift office, the open cardboard box, no individual access log, and the absence of a documented transfer between the MP locker and the CID custodian. The seal was intact when the custodian received it and at the lab, which helps, but it does not cure the gap. Chain-of-custody defects usually go to weight, not automatic inadmissibility; the military judge decides authentication under MRE 901 and may admit the evidence if there is sufficient proof that it is what the government says it is. But a serious unexplained gap can support exclusion or, more realistically, give the defense a strong argument. The agent should not reconstruct or 'fix' the record. He should interview the desk sergeant, obtain the shift roster, video, and access logs, and document who had access to the box. He should disclose the gap to trial counsel and prepare to explain it honestly. The lab's note about the folded, not fully heat-sealed corner is a separate packaging issue that should be documented and preserved.
2. What should the agent do about the field-test kit and the discrepancy between 12.4 grams and 11.9 grams?
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The 0.5-gram difference is not automatically evidence of tampering. Field scales are less precise and may be uncalibrated; the field figure is gross weight and may include the bag, while the lab figure is net. Moisture and handling can also account for a small loss. The agent should preserve the field-test kit, the field scale, any calibration records, and the original packaging; he should not discard the kit after a positive field test. He should obtain the lab's analytical report and weight certificate and ask the lab to explain the difference. If the agent did not personally weigh the item, he must say so and identify who did. He should avoid testifying that the weights are 'the same' or guessing. The defense is entitled to the discrepancy; the agent should disclose it rather than minimize it. If the field-test kit was destroyed, that is a preservation problem to report to trial counsel.
3. The defense alleges the MP desk sergeant planted the drugs. What investigative steps and documentation are appropriate?
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Treat the planting allegation as a lead, not an insult. The agent should preserve all evidence, including the shift-office video, the desk sergeant's timecard, the locker access log, and any texts or calls. He should interview the desk sergeant and any MPs on duty, but if the sergeant becomes a suspect, give Article 31(b) rights before accusatory questions. He should check whether the sergeant had any contact with the vehicle, the driver, or the bag, and whether the bag's seal and markings are consistent with the agent's original packaging. He should document the allegation verbatim and notify the supervisor and trial counsel; exculpatory information must be disclosed. He should not confront the sergeant informally in a way that creates a coercion issue, and he should not destroy his own notes. If the allegation has substance, a separate administrative or criminal investigation may be needed.