Forensic Analysis of Chemicals in Trap Cases – Part 1

A trap is a method of deliberate laying of the bait and catch the accused person red handed.

‘Bribery’is a term used for any act of giving gift or money, with dishonest nature for altering its recipient‘s behavior.

Bribery is an offence and may be defined as the offering, giving,receiving or soliciting of any valuable item for altering the conduct any person bearing a legal or public duty. ( Section 171 B of Indian Penal Code, 171E- Punishment for bribery )

Bribe is defined as a valuable thing which is offered to the other person for their own profit. It can be anything such as money, property, any promise, advantage etc.

A case is registered under Sections 7, 11, 13(1) (a) and 13(1) (b) of PC Act, 1988, for accepting bribe .

In trap related cases, phenolphthalein powder is used as a proof that the person has accepted the bribe. Below are some of the Chemicals , their properties and detection in forensic analysis of Trap Cases.

IMPORTANT POINTS ABOUT PHENOLPHTHALEIN

• Phenolphthalein is being used in most of the anti- corruption cases.
• A white, crystalline compound, C₂₀H₁₄O₄, used as an indicator in acid-base titration. An organic compound of the phthalein family that is widely employed as an acid-base indicator. It is an organic compound used as a laboratory reagent and pH indicator.
• As an indicator of a solution’s pH, phenolphthalein is colorless in acidic and attains a pink to deep red hue in basic solutions.
• Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols.
• It also serves as a component of universal indicator, together with methyl red, bromothymol blue, and thymol blue.

SYNTHESIS

• Phenolphthalein can be synthesized by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions.
• The reaction can also be catalyzed by a mixture of zinc chloride and thionyl chloride.

PROPERTIES

FORMS OF PHENOLPHTHALEIN

1. Under strongly acidic conditions, it exists in protonated form (HIn⁺), providing an orange coloration.
2. Between strongly acidic and slightly basic conditions, the lactone form (HIn) is colorless.
3. The doubly deprotonated (In^2-) phenolate form gives the pink color.
4. In strongly basic solutions, phenolphthalein is converted to its In(OH)³⁻ form, and its pink color undergoes a rather slow fading reaction and becomes completely colorless above 13.0 pH.

PRINCIPLE OF INVESTIGATION OF TRAP CASES

A trap can be laid in 3 scenarios. To catch the bribe taker, to catch the bribe giver, and the cross-trap: to catch both, the bribe giver and the bribe taker. The third type of trap is usually done with an intelligent input from an independent third source.

• First step is to complaint whenever to set a trap. The complaint is registered at official place.
• Then, verification of complaint and complainant takes place. it has been verified that whether the complaint is genuine or not. The complainant must not have any personal grudges or any enmity against the accused. It has been make sure that this is not being done to take any of the revenge.
• Investigation’s process:
• For verification, a sub-inspector may have to go with the complainant as his friend/brother/relative. It is a pre-planned arrangement between them that the complainant will simply request the accused to process his file/do his public duty without any hint of any bribe or the money.
• The accused must himself demand the bribe in exchange for discharging his public duties. The complainant is asked to keep this communication as brief as possible as more time with accused means more chances of error.
• Once the demand has been made, the complainant, then, in the course of communication, may try to negotiate the amount with the accused so that the demand made by the accused gets confirmed and the same is recorded on the camera and the bugging device.
• Note that in any condition, the complainant should not initiate any mention of the money by himself. The accused may smell something fishy and the case may go bust. It also weakens the case at later stages of the trial.

TRAP KITS

A trap kit should contain:

• Sodium carbonate.
• Currency notes smeared with phenolphthalein powder. The denomination and serial numbers of Government Currency notes are already noted down.
• Bottle containing distilled/mineral water (2×500 ml.).
• Tea spoon, beakers (2×500 ml.).
• Glass bottles with leak-proof lids (minimum 150 ml.).
• Paper envelopes for keeping currency notes and marking cloth for sealing exhibits.
• Labels for sticking on bottles, carbon paper, paper, candle and match box.
• Cotton roll and disposable gloves.
• Equipment for video recording and voice recorder.
• Trap Laying Officer should carry a mobile phone with him for videography / photography.

PLACES TO SEARCH FOR EVIDENCES

• Currency notes-their denomination and serial number are again noted down. The investigator should be satisfied that the currency is genuine.
• Hand wash of bribe taker on which phenolphthalein got transferred.
• Wash of pocket of shirt/pants/coat/other clothes in which currency notes are kept.
• Wash of table/drawer of table, file or paper on which notes are kept.
• Videography, voice recorder for recording of conversation between the accused and the complainant on the day of the trap and before the time of trap.

COLLECTION OF EVIDENCE

• Wash both the hands of the accused separately in 2–3 % sodium carbonate solution prepared in distilled water. The colourless solution changes to pink colour due to presence of phenolphthalein powder. This pink solution should be transferred to transparent and clean bottles.
• The currency  notes containing phenolphthalein are recovered and taken in possession from the place where they are kept by the accused like in the pocket/ drawer/briefcase/file paper of a drawer or table where in contact has taken place.
• Voice recording of conversation of accused  and complainant at the time of demanding money and at the time handing over the money should be videographed, if feasible.
• Photographs should be taken.
• The traces of phenolphthalein from the suspected surface may be lifted using a cotton swab soaked in sodiumcarbonate solution, squeeze out the solution in a clean glass bottle and put the swab in the same bottle.

HOW PEOPLE ARE CAUGHT RED-HANDED ?

Phenolphthalein is used, during trap cases as proof of acceptance of bribe. Phenolphthalein powder is spread on the currency notes and other objects which are likely to come in contact with hands of the perpetrator resulting in its transfer (based on Locard‘s principle of exchange) [It states that whenever two objects come in contact, there is always transfer or exchange of any material.]

• The perpetrator accepts the bribe and obviously touches the currency notes unknowingly that it contains phenolphthalein powder on it.
• Now, the hands of the perpetrator is washed with a colorless solution of sodium carbonate (or sometimes with lime water), which becomes immediately pink that confirms the touching of currency notes or the transfer of phenolphthalein to the hands of the perpetrator.
• Now, the evidences are collected and are sent to the laboratories.
• The color of phenolphthalein may fade away due to formation of 2(4 –hydroxy benzoyl) benzoic acid and phenol in under basic condition.
• The color of the solution must be photograph to represent it as evidence at the time of trial in the court.

ANALYSIS OF PHENOLPHTHALEIN

• pH Test: the pH of the solution is examined with the pH paper. More than pH 9 (range 8.3-10) with pink /red color shows the positive test for the presence ofphenolphthalein.
• Acid –Alkali Test: On addition of few drops dilute hydrochloric acid(HCl), pink colour disappears. Now add few drops of dilute solution of sodium hydroxide(NaOH) in water, the pink colour reappears. Appearing and disappearing of pink colour indicates the positive test for the presence of phenolphthalein.
  

PREPARING AN EXTRACT FOR FURTHER CONFIRMATION

Appropriate amount of hand wash in a 100 ml beaker is taken. This solution is acidified with dilute hydrochloric acid. The solution is extracted with 3×30 ml of diethyl ether. The extracted residue was crystallized with hot water as white crystalline mass. The ether extract is concentrated for further analysis

THIN LAYER CHROMATOGRAPHY

Mobile Phase:

• Benzene: Dioxane: Acetic acid (75: 15: 10)
• Chloroform: Acetone (4:1)
• Ethyl acetate: Methanol: Ammonia (80:10:5)
• Stationary phase: Silica Gel G

Visualizing reagent:

• UV light
• Exposed to ammonia vapor
• Spray with neutral ferric chloride solution.
• Iodine fumes
• With 1 % solution of potassium permanganate in 0.25 M sulfuric acid.

The ether extract is loaded on a silica gel plate.
Standard phenolphthalein was used for comparing.
The plate was developed in a suitable solvent system and then sprayed with the suitable spraying reagent given below.
TLC plate was exposed to ammonia vapor for visual development of undecomposed phenolphthalein as pink spot.
Alternatively all the spots should be visualized by iodine fumes treatment of the developed plate and compared with the standards.

UV-SPECTROSCOPY

Take UV spectra of this compound in aldehyde free alcohol gives absorbance maxima at 225 and 285 nm.

A Normal UV spectrum of phenolphthalein is known to show maxima at 277 nm in methanol.

It was found that the first and second derivative UV- spectra of the ethanol solution is more informative and is more specific.

·High Performance Liquid Chromatography (HPLC)

The ether extract were separately evaporated to dryness in glass capsules on water bath. The residue in each capsule was dissolved in about 1 ml of methanol and these separately prepared methanol solutions of exhibit and control were subjected for HPLC studies.

Mobile phase of isocratic solvent system comprising of water: methanol (75:25) was used.

 A flow rate of 1 ml / min and UV absorption detection at 277 nm at ambient temperatures were maintained throughout the experiment.

Under these conditions we can detect phenolphthalein up to 1µg in anticorruption cases.

High Performance Thin Layer Chromatography (HPTLC)

The concentrated / evaporated ether extracts from the different case exhibits, one control sample of phenolphthalein and one blank sample were separately spotted (5 ml each) as band (for better resolution) by using an auto sampler on dried and precoated silica gel 60 F – 254 HPTLC (20×20 cm) glass plate.

Solvent system – chloroform: acetone (9:1) was used for development of plate up to a distance of 10 cm.

The developed and dried plate was studied on HPTLC densitometer for maximum absorbance at 220 nm and densitometer scanning between 200 nm to 300 nm wavelengths for spectrum of each extract.

After development of the HPTLC plate, spots were located under UV visualization chamber by absorbing in short wave UV region at 254 nm. One of the spot of each sample tallies with the control phenolphthalein.

The developed and dried HPTLC plate was also exposed to ammonia vapours. The pink spot of all the exhibits tallied with the control sample, which confirm the presence of phenolphthalein

INFORMATION REVEALED AFTER FORENSIC EXAMINATION

• Establish the presence or absence of phenolphthalein and sodium carbonate in the pink solution.
• Presence of phenolphthalein on currency notes.
• Presence/absence of phenolphthalein residue in the pockets of clothes, briefcase, etc.

RELATED ISSUES

The coloured alkaline phenolphthalein solution unfortunately has a tendency to fade away with passage of time due to chemical changes. If the initial solution is highly coloured, with passage of time varying up to several months, its intensity may decrease but still it will be patently visible. On the other hand, if the alkali solution of phenolphthalein was only pink to light pink initially, because of very low quantity of transferred chemical it may become faint or even colourless after several weeks to months.

 Consequently when this physical evidence is finally produced in the court, often several months to year or more after the initial trap, the alkali solution may appear to be colourless or almost colourless. As the courts place reliance on the visual appearance of red colour of the alkali solution of phenolphthalein as a proof of transfer of phenolphthalein. The absence or doubtful presence of phenolphthalein complicates matters. Defense often tries to take advantage of this situation. Although this problem has been solved by adding small quantity of hydroquinone (an antioxidant).

HYDROQUINONE

The presence of hydroquinone will provide another parameter to prove the transfer of money especially in those cases when the plea is taken by the culprit that he uses phenolphthalein tablets as laxative. The presence of hydroquinone can be easily established on the basis of chemical and instrumental methods.

Thus phenolphthalein used in trap cases is replaced by mixture of phenolphthalein and hydroquinone (100:2); the resulting pink color does not fade appreciably after 4 years and can be seen by naked eye. Hydroquinone is a colorless powder and does not give pink color in alkaline medium.