Time since contact influences DNA profiling success of cartridges and fired cartridge casings.

Forensic DNA analysis of cartridges and fired cartridge casings remains challenging, possibly due to the heat and pressure generated during firing of the weapon as well as metal ions from the casings that have been suggested to initiate DNA degradation and inhibit PCR during the DNA profiling process. Even though recently developed DNA recovery protocols have shown to significantly improve DNA yields and DNA profile success rates no information is available on whether the time interval between contact and the DNA recovery process has an influence on these outcomes. In the current study 40 cartridges and 40 fired cartridge casings were left untreated for 24 h or 1 week after which the rinse-and-swab technique was used to collect DNA.

Evaluation of infrared photography for latent bloodstain visualization and the influence of time.

The localization of latent blood traces at crime scenes is generally performed using fluorescent stains although infrared light has previously been recognized as an effective localization test for bloodstains as it is a non-destructive and non-contact technique. The goal of this study was to evaluate infrared photography for the detection of latent bloodstains on a large number of objects with different compositions frequently encountered at crime scenes. In this study we show that infrared light photography was able to detect bloodstains deposited on 71.