Both DNA profiling and BPA are important to an investigation, yet they do not provide an estimate of when the crime occurred. Determining the amount of time that has elapsed since a bloodstain was deposited, or time since deposition (TSD), could provide important context to investigators. This is especially useful in cases where blood is the only biological evidence present; a timeline could be established and used to corroborate physical evidence, witness testimonies and the suspect alibis . Alternatively, TSD can be used to determine whether a bloodstain is relevant to the current investigation . Bloodstain TSD is typically estimated by modelling the physicochemical degradation of blood biomolecules over time; experimental methodologies generating spectroscopic , genetic and photographic metrics have been developed and used to estimate bloodstain TSD. Factors like individual variation, type of substrate and environmental conditions influence the timewise degradation of bloodstains and their biomolecules, resulting in large variability in the accuracy and precision of TSD estimation models .