The Netherlands Forensic Institute (NFI) said Friday it has developed a new forensic method that can help link suspects to explosions involving firework bombs. It does so by detecting traces of flash powder on skin or clothing. These traces can then be connected to actions such as building or transporting explosives.The institute said the technique focuses on residues from flash powder. Flash powder is commonly used in illegal fireworks such as the Cobra 6. A key measurable component of flash powder is perchlorate. This substance can be detected through forensic analysis.