Human airborne eDNA as forensic evidence in simulated residential burglaries.

Airborne environmental DNA (eDNA) is emerging as a valuable tool in forensic genetics to support individual identification in cases where other biological traces are limited or absent. Here, we investigate the potential of human airborne eDNA as a source of forensic evidence by evaluating its recovery following simulated residential burglaries. A total of 391 eDNA samples were collected from air, dust, and surfaces in 22 households by two laboratories. Samples were recovered under two conditions: immediately after residents vacated the premises and following a 15-minute simulated burglary. Resulting DNA profiles were compared against reference databases of residents and intruders. Under normal occupancy, air samples detected regular occupants, whereas airborne eDNA collected 30 min after simulated burglaries identified intruders in 82% of cases in one laboratory and 36% in the other. When combined with dust and surface samples, airborne eDNA provided additional evidence for detecting legitimate occupants, including past visitors. Variation in eDNA recovery across households and laboratories likely reflects differences in occupancy patterns, shedding abilities, cleaning and environmental conditions. This study demonstrates that, under controlled short-delay conditions, airborne eDNA can recover intruder-associated DNA profiles after brief occupancy, supporting its potential as a complementary source of forensic information.