The presence of blood at a crime scene can provide investigators with a treasure trove of information regarding the nature and circumstances of a particular crime and aid in crime scene reconstruction; however, attempts at concealing blood are common scenarios. The development of chemiluminescent and fluorescent-based presumptive tests, such as the luminol and fluorescein tests, have made it more challenging to definitively remove or mask blood on a surface. The purpose of this experiment was to qualitatively measure the overall efficacy of luminol, concerning its ability to positively detect small bloodstains found on common household floor surfaces (wood, carpet, and tile) that have either been cleaned with bleach, painted, or both bleach-cleaned and painted. The results of the three experiments concluded that luminol was ineffective at detecting small, fresh bloodstains on tile or wood surfaces that had been either painted over or bleach cleaned and painted over but was effective at detecting small, fresh bloodstains on carpet that had been cleaned with bleach (50% and 100%) and painted with up to 10 layers of solvent-based paint.
"Qualitative Analysis of Luminol Efficacy on Bleach-Cleaned and Paint-Concealed Blood,"
Themis: Research Journal of Justice Studies and Forensic Science: Vol. 8
, Article 1.