Donovan chooses chemical formulas for his forensic cleaning kit at his home in Texcoco, Mexico on May 21, 2015. Donovan prefers not to write down or otherwise record the 370 formulas he has memorized for his work, so they cannot be stolen. Donovan Tavera, 43, is the director of “Limpieza Forense México”, the country’s first and so far the only government-accredited forensic cleaning company. Since 2000, Tavera, a self-taught forensic technician, and his family have offered services to clean up homicides, unattended death, suicides, the homes of compulsive hoarders and houses destroyed by fire or flooding. Despite rising violence that has left 70,000 people dead and 23,000 disappeared since 2006, Mexico has only one certified forensic cleaner. As a consequence, the biological hazards associated with crime scenes are going unchecked all around the country. Photo by Bénédicte Desrus