Detective Dye
Definition
A powder (typically anthracene or phenolphthalein-based) applied to banknotes or surfaces. Transfers to the suspect's hands on contact; anthracene fluoresces under UV while phenolphthalein turns pink in an alkaline wash, used in trap cases by Indian vigilance teams.
- Composition
- Fluorescent powder, typically anthracene or phenolphthalein-based
- Application
- Applied to banknotes or surfaces before a trap operation
- Detection method
- Fluoresces under UV light after skin contact
- Common use
- Trap cases run by Indian vigilance and anti-corruption teams
Common questions
How does a detective dye actually catch a suspect after the money changes hands?+
The powder is invisible under normal light and transfers onto the suspect's hands the moment they touch the treated notes, and because it fluoresces strongly under an ultraviolet lamp, investigators can demonstrate contact even if the suspect later denies handling the marked currency.
Can a detective dye result be challenged in court?+
Yes, defence arguments often focus on chain of custody for the treated notes, whether the dye could have transferred through indirect contact, and whether proper controls, such as a pre-trap hand check, were documented, so procedural rigour around the application and testing matters as much as the fluorescence result itself.
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