Suz Brothwood

Forensic Science
Gwyddoniaeth Fforensig

Impact of hand sanitiser and increased hand hygiene on the detection of latent fingerprints.

Effaith glanweithdra dwylo a mwy o hylendid dwylo ar ganfod olion bysedd cudd.

In 2020 the coronavirus (C19) pandemic brought to light the importance of hand hygiene, this can be seen by the rapid increase in sales of hand sanitisers and soaps, bringing into question whether this increase and the use of sanitisers can affect the detection methods used on latent fingerprints at crime scenes. It is important for forensic investigators to be able to develop latent prints however the use of hand sanitisers may change the way in which fingerprints are left or the effectiveness of the detection techniques making development either easier or more difficult. Additives such as humectants within the hygiene products could enhance the development techniques allowing for better developed prints. Based on this hypothesis, this research project analysed two alcohol hand sanitiser and two liquid hand soap to determine their effect on how fingerprints are left and the detection techniques that will be used. The fingerprints were taken from two donors, one male and one female, onto two different surfaces: glass, and plastic. They were asked to either wash their hands with liquid hand soap for twenty seconds (as stated in government guidelines) or use one pump of hand sanitiser, then they were asked to deposit their prints onto the individual surfaces straight away, ten minutes, thirty minutes and one hour later. Two types of detection methods were used to develop the latent fingerprints: magnetic powder (MP) and cyanoacrylate (CYA) fuming, once development had been carried out the results were photographed using a Huawei P30 pro camera phone. The research revealed that latent prints were still developable after soap or sanitiser use. MP was successful in developing partial to full prints overall, most of the male deposits were successfully developed whereas for the female CYA prints struggled to develop more than a partial print.

Yn 2020 daeth pandemig y coronafeirws (C19) â phwysigrwydd hylendid dwylo i’r amlwg, gellir gweld hyn drwy'r cynnydd cyflym yng ngwerthiant diheintyddion dwylo a sebon, gan ystyried a all y cynnydd hwn a'r defnydd o ddiheintyddion effeithio ar y dulliau canfod a ddefnyddir ar olion bysedd cudd mewn lleoliadau troseddu. Mae'n bwysig i ymchwilwyr fforensig allu datblygu olion bysedd cudd, ond gall defnyddio diheintyddion dwylo newid y ffordd mae olion bysedd yn cael eu gadael neu effeithiolrwydd y technegau canfod sy'n gwneud datblygiad naill ai'n haws neu'n fwy anodd. Gallai ychwanegion fel gwlybyryddion o fewn y cynhyrchion hylendid wella'r technegau datblygu gan ganiatáu ar gyfer argraffiadau datblygedig gwell. Yn seiliedig ar y rhagdybiaeth hon, dadansoddodd y prosiect ymchwil hwn ddau hylif diheintio dwylo gydag alcohol a dau sebon llaw hylif i benderfynu ar eu heffaith ar sut mae olion bysedd yn cael eu gadael a'r technegau canfod a ddefnyddir. Cymerwyd yr olion bysedd gan ddau roddwr, un dyn ac un ddynes ar ddau arwyneb gwahanol: gwydr a phlastig. Gofynnwyd iddynt naill ai olchi eu dwylo gyda sebon llaw hylif am ugain eiliad (fel y nodwyd yng nghanllawiau'r llywodraeth) neu ddefnyddio un pwmp o hylif diheintio dwylo, yna gofynnwyd iddynt roi eu holion bysedd ar yr arwynebau unigol ar unwaith, deng munud, tri deg munud ac un awr yn ddiweddarach. Defnyddiwyd dau fath o ddulliau canfod i ddatblygu'r olion bysedd cudd: powdr magnetig (AS) a mygdarthu syanoacrylad (CYA), ar ôl i'r datblygiad gael ei wneud ffotograffwyd y canlyniadau gan ddefnyddio camera ffôn Huawei P30 pro. Datgelodd yr ymchwil fod printiau cudd yn dal i gael eu datblygu ar ôl defnyddio sebon neu ddiheintydd. Roedd MP wedi llwyddo i ddatblygu printiau rhannol i lawn yn gyffredinol, datblygwyd y rhan fwyaf o'r dyddodion gwrywaidd yn llwyddiannus ond ar gyfer y ddynes roedd printiau CYA yn ei chael hi'n anodd datblygu mwy na phrint rhannol.