What chain of custody is technically
Sequential document recording: who had the evidence, when, in what state, for what reason, with what tool, in what location, with what environmental control, which cryptographic hash verifies integrity. Each transfer (between experts, labs, court and lab) is a new entry. Chain begins at seizure and ends at trial or authorized disposal. Failure in any entry = attack point for contestation.
Failures that invalidate chain of custody
- 1.Seizure without witnesses. At least 2 people present at original collection. Document signed by both. Without this, easy contestation.
- 2.Period without record. Gap between one entry and another (e.g., 'received Jun 10', next entry 'Jul 20') invalidates the interval. Every movement registers.
- 3.Inconsistent hash between transfers. Hash at delivery must match hash at receipt. If diverges, contestation claims transport alteration.
- 4.Missing numbered seal. Media must travel sealed between transfers. Numbered seal recorded on both sides. Without it, media swap is alleable.
- 5.Analysis in uncontrolled environment. Analysis must be in lab with access control, cameras, records. Analysis in regular office is contestable.
- 6.Expert without documented credential. Expert must have registered training. CV attached to report.
FAQ
Which law defines chain of custody?
In Brazil: Law 13.964/2019 (Anti-crime Package) added articles 158-A to 158-F to Criminal Procedure Code. Technical standard: ABNT NBR ISO/IEC 27037:2013 (digital evidence preservation). Similar standards exist in US (NIST SP 800-86) and EU.
Who signs the chain of custody?
Each person who handled the evidence. Minimum: seizure agent, technician who received, expert who analyzed, archive responsible. Dates, times, physical or digital signatures.
Does digital chain replace paper chain?
Yes when signed digitally with certified credential. Mix between digital and paper is allowed as long as each link is valid.
How long is chain maintained?
Until final judgment of last action that may cite evidence. In civil: 10-20 years typically. In criminal: until prescription of maximum sentence, which may reach 30+ years.
Can I use HD Doctor report in proceedings?
Yes. Our reports follow ISO/IEC 27037 and relevant laws. Engineers credentialed as experts. Complete documentation attached to report. We work directly with law firms, prosecutors and police.
Need expert report with valid chain of custody?
Report compliant with ISO 27037. Team credentialed as expert witness.