Francisco García Escalero and Spain's Invisible Murders Between 1987 and 1993, a severely mentally ill homeless man named Francisco García Escalero murdered at least eleven people on the streets of Madrid, selecting his victims from among Spain's most marginalized populations—fellow homeless individuals whose deaths would generate minimal investigation or public concern. Known as "El Matamendigos" (The Beggar Killer), Escalero's crimes involved horrific mutilation and cannibalism, yet his case raised profound questions about criminal responsibility when severe mental illness destroys the capacity for moral choice. This meticulously researched account traces Escalero's descent from troubled youth through years of untreated paranoid schizophrenia and homelessness to his emergence as a serial killer driven by command hallucinations. The book examines his 1995 trial, where Spanish courts grappled with whether psychotic illness could negate criminal responsibility even for the most heinous crimes, ultimately declaring him legally insane and confining him to indefinite psychiatric hospitalization rather than prison. Beyond the individual case, this work explores how social marginalization creates vulnerable populations that predators can attack with impunity, how mental health and social service systems catastrophically failed both Escalero and his victims, and how society's indifference to certain lives enables violence that would be unthinkable against more privileged victims. This is both a compelling true crime narrative and a sobering examination of institutional failure, psychiatric justice, and the deadly consequences of rendering human beings invisible.