Abstract
Sexual crimes represent a significant challenge for criminal investigation, requiring accurate methods for identifying biological traces. The use of forensic light and immunochromatographic tests for detection of PSA has shown promise, although there are limitations in discriminating bodily fluids. When it comes to forensic samples, it is not always possible to visualize the stain to be analyzed, as it is also common for biological material to be mixed in the supports sent for analysis. Therefore, the objective of the present study was to evaluate the effectiveness of the combination of forensic light and immunochromatographic testing for PSA detection in identifying semen under different storage conditions. Samples of semen, urine and mixtures of both were prepared in tissue fragments and subjected to different storage conditions (paper and plastic) for up to 20 days. The results showed that forensic light is efficient in locating biological stains but does not discriminate between fluids such as semen and urine. The PSA test, on the other hand, showed high specificity for detecting semen, regardless of the type of casing, although the intensity of detection decreased in samples stored in paper for 20 days. The analyzes reinforce the need to combine methods for greater precision in identifying biological evidence in sexual crimes.