Profile: Consider the evidence
'I've yet to work the same day twice!' she enthuses. Her work as a student involved months of the same repetitive experiments, she recalls. But now she has left that all behind. 'Given the variety of evidence encountered, we are often called on to modify or develop, then validate, processing methods,' she says.
Burk is a forensic analyst for the City of Eugene Police Department in Oregon, US. The unit where she works provides scientific analysis to aid a wide variety of criminal investigations, from homicide, burglary and forgery to sexual assault. While many forensic laboratories contain more specialists than generalists, Burk's group do both crime scene and laboratory work.
Leave no scrap of paper unturned
For example, Burk's team may be called to process a robbery at a store where a note was used to communicate the robbers' intentions. The note, taken as evidence, is taken back to the lab, where it can be evaluated to determine suitable fingerprint-processing techniques, and fully documented and recorded. For a handwritten note on plain white paper, says Burk, a standard method is the application of ninhydrin (2,2-dihydroxyindane-1,3-dione), in an HFE-7100 based solution. HFE-7100 is a selective solvent; it is inert to most inks and does not appreciably dissolve the amino acids transferred to the porous substrate in a fingerprint. It has a low surface tension compared with hydrocarbon solvents like petroleum ether, which allows it to more easily and thoroughly carry dissolved ninhydrin to where it is most useful - namely the edges of the fingerprint ridges. After a suitable incubation period, purple ridge details appear. 'This is just one of the chemical processing techniques possible for this note,' says Burk.
Each case that her team works on could lead to testimony in court. She says that her experience at university - presenting data to fellow students and staff or at conferences, alongside teaching assistantships - prepared her well for this part of the job.
So once you've landed your dream job, where do you go next? 'For career development, my immediate focus is my PhD defence - something many grad students can relate with!' says Burk. Early in graduate school she had the opportunity to work on a joint academic lab/crime lab project. 'I hope to participate in such a project again,' she says, 'this time from the crime lab side.'