Literature searches were conducted in two databases: Web of Science and Scopus. The searches included full-text articles, summaries, and abstracts. Searches were conducted in English and did not include a restriction for the year of publication. Following the searches, which were completed 12 May 2021, databases were searched using a combination of the following keywords: 'DNA', 'RNA', 'time since deposition', 'bloodstains', 'hemoglobin', 'taphonomy', 'blood', 'degradation', 'forensic', 'spectroscopy', 'metabolites', 'proteins', 'plasma proteins', 'aging', 'volatile organic compounds', 'transcriptome', 'methylation'. The combination of keywords was done through the Boolean operator 'AND' and resulted in 26 searches. The number of hits for each search is found in Table . Hits were imported into EndNote citation manager for eligibility assessment.