Success rates of a forensic tape-lift method for DNA recovery

In or der to en trap and lift trace ev i dence at tached to sur faces of ev i dence ma te rial for fur ther fo ren sic in ves ti ga tion, the use of ad he sive sur faces such as foils or tapes has be come a com monly used re cov ery ap proach in a broad range of fo ren sic dis ci plines. Among the ad he sive lift ing ap pli ca tions in use to day are the re cov ery of tex tile fibres, hair, shoeprints, paint traces, fin ger prints, gun shot res i dues, cel lu lar ma te rial and DNA [see e.g. 1, 2, 3, 11, 13, 15, 17]. The ap proaches used are still be ing de vel oped into even more so phis ti cated ap pli ca tions [18, 20] and com bined ap proaches us ing ad he sive tapes for more than one fo ren sic pur pose have, for in stance, been pre sented for gun shot res i dues and DNA [3, 15] and DNA anal y sis af ter the de vel op ment of fin ger prints [12, 21]. Ad he sive tape ap plied di rectly to the skin has also been sug gested as an al ter na tive to other more in va sive means of ref er ence DNA sam pling from in di vid u als [7]. Find ing DNA traces on the ev i dence re quires dif fer ent strat e gies de pend ing on trace type, the ex hibit and case cir cum stances. While blood stains are of ten quite eas ily found upon vi sual in spec tion, other stains from e.g. se men, sweat or sa liva may not be de tected by the na ked eye, but rather by their flu o res cence us ing a fo ren sic light source such as a CrimeScope CS-16-400 (SPEX Fo ren sics, Olathe KS, USA). Stain lo cal isa tion is fur ther com pli cated by the fact that sa liva stains are not al ways pos si ble to de tect by the na ked eye or with a fo ren sic light source [4], re sult ing in a need to com bine stain search with pre-test ing tech niques. Fur ther more, DNA traces orig i nat ing from skin ep i the lium or other con tact traces not de tect able by a fo ren sic light source might still be pres ent but over looked. More over, not all stains visu al ised are of hu man or i gin, which is a rea son for a sub stan tial level of neg a tive Problems of Forensic Sciences 2010, vol. LXXXIII, 243–254