Ann Arbor Hospital murders

During a period of a few months in 1975, patients at the Veterans Administration hospital in Ann Arbor, Michigan, began experiencing respiratory failure and, in some cases, death with unusual frequency. On a single day in mid-August, three patients required emergency treatment within a 20-minute period to save their lives. The chief of anesthesiology determined that the patients responded to an antidote for a paralyzing drug, prompting the hospital to call in the FBI. The case was later documented in a case series in the New England Journal of Medicine.

The FBI investigation identified nurse Filipina Narciso as having been on duty in the relevant ward during every poisoning. One patient identified her as the nurse who injected something into his IV shortly before his breathing stopped, though he died before trial. Nurse Leonora Perez was similarly identified by another patient who also died before the trial. Assistant U.S. Attorney General Richard Delonis described the case against the two as "highly circumstantial," though defense lawyers considered it strong enough that they put Narciso and Perez on the stand, where they appeared evasive.

The trial was marked by accusations of racism. Both defendants were recent immigrants to the United States, and one man originally slated as the prosecution's lead witness referred to them using an ethnic slur and alleged a nationwide conspiracy of Filipino nurses to murder veterans. Racial tensions in the case were heightened by broader national tensions related to immigration from Asia at the time. The prosecution's case emphasized the regular proximity of Narciso and Perez to poisoned patients, including testimony from a relative of one victim describing one of the defendants doing something to bedside equipment shortly before the victim stopped breathing. Prosecution experts argued that Pavulon injections must have occurred only minutes before patients showed paralysis and stopped breathing.

The jury acquitted Narciso and Perez of the single murder charge under consideration but found both guilty of three counts of poisoning and conspiracy to poison patients. Pacifico Marcos, president of the Philippine Medical Association and brother of Philippine President Ferdinand Marcos, headed a defense fund and called the verdicts a "miscarriage of justice." In February of the following year, a judge set aside the guilty verdicts, ruling that the jury—which had deliberated 15 days and had acquitted on the murder charge and some poisoning charges—may have been influenced by prejudicial elements in the prosecution's presentation.

The new attorney general declined to pursue another prosecution, reportedly because public opinion did not support prosecuting the nurses further, and because the defendants were unlikely to testify again and expose themselves to cross-examination. The prosecution became a rallying point for protest groups and Filipino communities who condemned the handling of the case and expressed support for both nurses. Public opinion had generally been skeptical that the nurses could have had any plausible motive for the poisonings.