**4.5. Analysis of explosives**

IR-enhanced photography may enhance the gunshot residue pattern [49, 50]. In a study performed in 2007 by Lin et al., gunshot residue was collected from dark cloth samples following firing from 15, 30 and 60 cm ranges using a 9-mm pistol (Smith & Wesson) with 9 mm bullets (NPA 01 3). Components that absorb the IR of gunshot residue were determined. The authors indicated that "the number of black particles observed using IR was approxi‐ mately 418, 317 and 63 within a 10 cm radius around the entrance hole when the firearm was discharged at distances of 15, 30 and 60 cm of shooting, respectively". Other features of this assay for the determination of distance shooting are that this test permits records and is not destructive for gunshot residue [48]. In another study, Patne et al. claimed that chemical imaging technology may be used to eliminate different brands of ammunition based on the fluorescence characteristics of the propellant grains on clothes without destroying the evidence before further analysis may be conducted [47]. Furthermore, Bueno et al. suggested the use of NIR-Raman microspectroscopy combined with advanced statistics to detect gunshot residues in 2012. Researchers claimed that NIR Raman microspectroscopy has the potential for reagentless differentiation of gunshot residues based on forensically relevant parameters, such as the calibre size, and this method should have a significant impact on the efficiency of crime

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Yine de girdiğiniz şu sorguyu mu aramak istiyorsunuz? Dolayısı ile olay yerinde kızıl ötesi dalga boylarını kaydeden bir cihaz kullanılması neticesinde kan lekelerinin fark edilebilirliği

Thus, the differentiation in the availability of blood stains in crime scenes increases when using a device noting IR wavelengths. This method is advantageous for precisely determining the morphology of blood stains. Furthermore, this method reduces the number of samples obtained from the crime scene depending on the quicker determination of materials at the crime scene and prevents the time spent and economic losses [16, 52]. Two studies demon‐ strated that in the detection of blood stains with an IR camera, better results were obtained by other methods even in blood stains 10-times diluted or found on the floor, which absorbs blood [16, 52]. In another study performed by Lin et al., blood stains diluted to a 1/8 ratio were viable in 8 of 10 different cloth samples by IR photography. Nevertheless, blood stains diluted to a 1/2 ratio were not viable in two fabric types, including 35% rayon and 65% polyester and 5%

It has been reported that the determination of blood samples and the identification of their ages on fabrics are possible using IR cameras. In the identification of the ages of blood samples, the cross-validated standard error of calibration was less than 1 week in optimal conditions

scene investigations when fully developed [51].

**4.4. Differentiation of blood stains**

108 Forensic Analysis - From Death to Justice

artmaktadır.

artmaktadır.

[53].

Blood is a substance that absorbs IR rays.

lycra and 95% cotton, via IR photography [48].

Fourier transform infrared (FTIR) and Raman spectroscopic techniques have been defined as powerful techniques used for the optimal identification of a broad range of explosives and related compounds. It has been reported that FT-Raman spectroscopy, which has a longer wavelength, is the preferred method for the fluorescence-free analysis of explosives when the conventional Raman spectra cannot be measured because of the fluorescence background [54].
