Shrub Oak opened in 2018 with grand promises: beautiful dorms, an indoor therapy pool, an equestrian stable, a restaurant-quality kitchen, sophisticated security, round-the-clock care and cutting-edge education for students with autism from around the world. Some of those promises never materialized. A ProPublica investigation — based on records from school districts, court documents and interviews with nearly 30 families and just as many workers — also found accusations of possible abuse and neglect: unexplained black eyes and bruises on students’ bodies, medication mix-ups, urine-soaked mattresses and deficient staffing. Many parents and workers, armed with confidential documents and photos of student injuries, described their futile efforts to get authorities to intervene.