How should questioned stains be collected from absorptive surfaces?

When collecting questioned stains from absorptive surfaces, cutting out the stained area is often the preferred method, particularly if the surface can be damaged or if the stain is embedded in the material. This technique helps to preserve the integrity of the stain and minimizes contamination or degradation that could occur if the stain was simply wiped or handled improperly.

This approach is especially relevant when considering potential inhibitors that could interfere with subsequent analysis. For instance, certain materials may contain chemicals or compounds that could degrade the quality of DNA or other forensic tests. By excising the portion of the surface containing the stain, the forensic analyst can better ensure that the sample collected is as pure as possible and that any potential inhibitors are removed from the equation.

This method ultimately aids in the reliability and accuracy of the forensic analysis to be performed later on the collected evidence.