The importance of considering common sources of unknown DNA when evaluating findings given activity level propositions

Emerging use of air eDNA and its application to forensic investigations – A review

“…There have been numerous cases in which an explanation has been put forward for the presence of an individual's DNA on an item that involves DNA shed to the surroundings and transferred, through the air, to an object (author's personal experience, but also for an example see the case scenario in Ref. [148]). Air sampling studies would provide information that can be used to inform scientists on the probability of such events occurring, which in turn would allow more informed opinions to be provided to investigators or in court [149,150].…”

“…Additionally, evaluation of DNA results at activity level is an important task that is increasingly requested from a forensic scientist [149]. Important aspects for activity level evaluations are the presence of background DNA and contamination and their contribution to the profile in question [148]. To date, contamination considerations have centred on person to exhibit or exhibit to exhibit contamination [150], but aerosol indirect transfer both prior to (part of the background DNA) and post action in question will need investigation.…”

Recent advances in forensic biology and forensic DNA typing: INTERPOL review 2019–2022

“…Following a comprehensive January 2019 review that cited [ 298 ] references on DNA-TPPR [ 14 ], the same authors provided an update in November 2021 on recent progress towards meeting challenges and a synopsis of 144 relevant articles published between January 2018 and March 2021 [ 297 ]. While few studies provide the information needed to help assign probabilities of obtaining DNA results given specific sets of circumstances, progress includes use of Bayesian Networks [ 300 ] to identify variables for complex transfer scenarios [ 38 , [301] , [302] , [303] , [304] , [305] ] as well as development of an online database DNA-TrAC 43 for relevant research articles [ 299 ] and a structured knowledge base 44 with information to help practitioners interpret general transfer events at an activity level [ 306 ].…”

A collection of idioms for modeling activity level evaluations in forensic science

“…One may also use separate BNs for each hypothesis. Cause-consequence idioms are frequently presented in forensic and legal research, whether in template models [ 3 , 9 , 13 , 26 , 27 , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] ] or case models [ [16] , [17] , [18] , [19] , [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] , [75] , [76] ]. …”

“…Both the hypothesis-to-activity idiom and the hypothesis-to-transfer idiom are essential in activity level evaluations and therefore appear in many forensic templates [ 9 , 48 , 54 , 58 , 59 , 61 , 62 ] and case models [ 32 , 64 , 65 , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] , [75] , [76] , 78 , 79 ]. Although earlier research involving template models and case models such as [ 42 ] has also focused on activity level examinations, the use of the hypothesis-to-activity idiom is, to the best of our knowledge, only notably present in later work (2015 until now) - with the exception of Evett et al [ 64 ].…”