Finger prints evidence is regarded as the best means of personal identification. It can also
distinguish between identical twins. The type of finger prints invisible to the naked eye is known
as latent finger prints. Recovery of latent finger prints from materials depends on a number of
factors such as type of material, environmental conditions and duration of exposure. Water
comprises about 71% of the earth. As the number of people visiting water ways (rivers, canals,
streams etc.) is increasing, the incident rate of crimes has been found to rise at these places.
Moreover, criminals find it convenient to dispose of weapons and evidences in the water ways.
Forensic science consists of a variety of techniques that are applied in order to answer the
questions of interest to legal system. Cyanoacrylate fuming and dusting powder methods are
used for the development of latent finger prints from materials immersed in aquatic environment.
By examining the characteristics of latent finger prints, on materials thrown in to water, the
forensic scientist may positively identify the perpetrator.
This research activity was conducted to evaluate the effect of type of material, immersion
medium and time length of immersion in aquatic environment, in a realistic setting, using
materials that closely resemble the common evidences. The materials comprised stainless steel
knives, aluminum foils, used brass cartridges, soft drink plastic bottles and glass slides. For every
material, sample size was kept 196. The samples were labeled with permanent identification
numbers. After deposition of finger prints by volunteers, the materials were placed in the tubs of
immersion media, one tub for each type of material. Maximum immersion time was 35 days. 21 samples of each material were taken out of water at day 5, 10, 15, 20, 25, 30 and 35. The
taken out 21 samples and 7 controls were processed for latent finger prints development, with
cyanoacrylate fuming and dusting powder methods.
Cyanoacrylate fuming was performed in a zip lock transparent polythene bag. A china
dish covered with aluminum foil and having NaOH treated cotton balls was introduced in the
fuming chamber. Samples, controls and a beaker of hot water were also placed. Cyanoacrylate
(ELFYTM) drops were put over the cotton balls and zip was closed immediately. The controls
were observed for optimum development of latent finger prints. After development, each finger
print was lifted using tape lifter, placed on a white finger print card and examined with the help
of a magnifying glass. The finger prints were assessed using a scoring system, based on the
visibility of finger prints, as adopted in various published studies.
Similar results were obtained for up to 5 days immersion in all the immersion media.
Differences arose from day 10. This time and onwards, finger prints could not be developed from
brass cartridges immersed in any media. Canal water was noted to favor the retention of latent
finger prints because suspended particles in canal water tend to adhere the latent finger prints.
Detergents in sewerage water were found to quickly wipe the latent finger prints residue.
Chlorine used as dis-infectant in swimming pools is acidic in nature. Under acidic conditions,
development of latent finger prints becomes difficult.
The data was analyzed for results by Pearson’s co-efficient of correlation using IBM SPSS
20.0 software. The study illustrated that there is correlation among type of material, immersion
medium and time length of immersion in aquatic environment. It will provide valuable
information for crime investigation agencies to establish a link between finger prints evidence
recovered from various materials immersed in aquatic environment and the suspected person.