DNA recovery after sequential processing of latent fingerprints on black polyethylene plastic.

Latent fingerprints on plastic substrates can be visualized by using sequential treatments to enhance the contrast between the fingerprint residues and underlying substrate; however, the extent to which these processes affect subsequent DNA analysis is mostly unknown. Latent fingerprints deposited on black plastic by one donor were visualized with single-process fingerprint powders (i.e.

DNA recovery after sequential processing of latent fingerprints on copy paper.

Forensic examiners must determine whether both latent fingerprint development and DNA profiling can be performed on the same area of an evidence item and, if only one is possible, which examination offers the best chance for identification. Latent fingerprints can be enhanced by targeting different components of fingerprint residues with sequential chemical treatments. This study investigated the effects of single-reagent and sequential latent fingerprint development processes on downstream DNA analysis to determine the point at which latent fingerprint development should be stopped to allow for DNA recovery.

Accelerated aging of forensically relevant biological materials on swabs.

The preservation of DNA in biological samples is important for forensic testing, as samples can be tested years or even decades after collection. Generally, the DNA within biological evidence is stable over shorter time frames but can degrade over extended periods. In this work, we evaluated accelerated aging as a method to reduce the duration of studies examining the stability of DNA in forensic evidence-type samples.

Direct PCR amplification of forensic touch and other challenging DNA samples: A review.

DNA evidence sample processing typically involves DNA extraction, quantification, and STR amplification; however, DNA loss can occur at both the DNA extraction and quantification steps, which is not ideal for forensic evidence containing low levels of DNA. Direct PCR amplification of forensic unknown samples has been suggested as a means to circumvent extraction and quantification, thereby retaining the DNA typically lost during those procedures. Direct PCR amplification is a method in which a sample is added directly to an amplification reaction without being subjected to prior DNA extraction, purification, or quantification.

Nondestructive Biological Evidence Collection with Alternative Swabs and Adhesive Lifters.

In forensic science, biological material is typically collected from evidence via wet/dry double swabbing with cotton swabs, which is effective but can visibly damage an item's surface. When an item's appearance must be maintained, dry swabbing and tape-lifting may be employed as collection techniques that are visually nondestructive to substrates' surfaces. This study examined the efficacy of alternative swab matrices and adhesive lifters when collecting blood and fingerprints from glass, painted drywall, 100% cotton, and copy paper.

ESDA®-Lite collection of DNA from latent fingerprints on documents.

The ability to detect and non-destructively collect biological samples for DNA processing would benefit the forensic community by preserving the physical integrity of evidentiary items for more thorough evaluations by other forensic disciplines. The Electrostatic Detection Apparatus (ESDA®) was systemically evaluated for its ability to non-destructively collect DNA from latent fingerprints deposited on various paper substrates for short tandem repeat (STR) DNA profiling. Fingerprints were deposited on a variety of paper substrates that included resume paper, cotton paper, magazine paper, currency, copy paper, and newspaper.