Mate Uses the Humanitron to Help Others Die

Eldon Mate’s use of the Humanitron made him, in effect, a doctor of assisted death: he used a homemade apparatus to help people die, and it had been used fifty times by the time of his own murder investigation. The device’s crude construction and the uncertain circumstances of some of its clients stand in sharp contrast to its reported effectiveness. Joanne Doss’s case brings the practice into the intimate territory of an unexplained illness, a family’s struggle to interpret decline, and a decision that Richard Doss later described with anger and blame.

Mate’s medical background

A biographical account on a webpage devoted to Mate traced an unusual route into medicine. Born in San Diego, he earned a chemistry degree from San Diego State and worked as an oil-company chemist before entering medical school in Guadalajara at forty. After an internship at a hospital in Oakland, he received his general-practitioner license at forty-six. He had no specialty training; the jobs described in news coverage were civil-service posts at health departments across the Southwest, where he oversaw immunization programs and handled administrative work. The account offered little indication that he had treated patients in conventional practice.

That professional history complicates the image of the physician behind the Humanitron. Mate possessed medical credentials, but the public record described a career largely outside ordinary clinical care. His assisted-death work therefore appears not as one service within a broad treatment practice, but as a distinctly separate undertaking. Reports of his career also recounted acquittals, though they did not provide details of the cases in the evidence presented.

The Humanitron and its reported use

Mate called his death apparatus the Humanitron and described its recipients as Happy Traveling. The name suggested a passage, while the apparatus itself was anything but polished: Milo Sturgis said it looked like a makeshift school science project, assembled from mismatched screws and unstable parts rather than advanced technology. Its roughness did not mean it failed. Milo reported that it had worked fifty times, a figure that made the investigation’s search for possible suspects daunting: each use implicated a family, and many of Mate’s chosen recipients had come from outside California.

The people who could be reached did not uniformly condemn Mate. Some described him as the only person willing to help when relatives were suffering and their doctors would not act. Investigators could not tell from telephone interviews whether these accounts were protective alibis or sincere expressions of belief. The police had assigned two new detectives to make calls, but the work was slow: many potential witnesses lived out of state, and some survivors were reluctant to discuss Mate. Milo wanted face-to-face interviews, with Alex Delaware potentially helping to interpret what people said, but the inquiries had so far been conducted by telephone.

Joanne Doss’s illness and the disputed meaning of her death

Joanne Doss’s case shows how Mate’s work entered a family already struggling to make sense of prolonged deterioration. Richard Doss said that he and Joanne had consulted dozens of doctors and that she had undergone extensive testing, including CAT scans, MRIs, blood tests, and two lumbar punctures. A later review of her file listed work by fifteen doctors, including blood and urine tests, X-rays, PET scans, further scans, and the spinal procedures Richard had mentioned. The results were described as negative; the records did not establish a cause for her suffering.

Richard recalled that the decline began with fatigue in a woman who had previously danced, played tennis, and powerwalked. Joint pain, headaches, skin sensitivity, and increasing exhaustion followed. Joanne gradually stopped socializing and going out to dinners, withdrew from country-club activities, and spent more and more time in bed. Her weight rose from 110 to 210 pounds in less than a year. Richard said food was the one thing she did not withdraw from, and he described feeling that his athletic young wife had become a stranger. A washed-out Polaroid made that change visible in a starkly different way: in a long view of a bed, a swollen face appeared among a mound of pillows, its features compressed by the weight of her condition.

The absence of a medical explanation did not produce a shared account of what was happening. Richard later characterized Joanne’s condition as psychological and said that she had chosen to withdraw from life; he believed psychiatric treatment and commitment might have changed the outcome. He also said she had called Mate to finish what her illness had begun. His account places Mate’s intervention inside a dispute over whether Joanne’s suffering was an unrecognized physical illness, depression, or a decision to die. The available medical records document extensive investigation without a diagnosis, not proof that her suffering was unreal.

Investigation and the apparatus’s reversal

Mate’s own death made the Humanitron both evidence of his practice and a possible disguise. He was found tied to the machine, with an intravenous line in each arm: one bottle contained thiopental, the tranquilizer he used, and the other potassium chloride, intended to cause cardiac arrest. His thumb touched the small trip-wire mechanism that started the flow. The coroner found that the potassium had begun to act, but the setup had not killed him. He had been struck hard enough to fracture his skull and cause a subdural hematoma, then mutilated; the apparatus was a staged appearance of the method he had used to help others die.

That reversal sharpened the distinction between Mate’s assisted-death practice and his murder. The Humanitron could represent, for grieving relatives, a response to suffering that conventional medicine had not relieved; at the murder scene, its familiar procedure instead concealed a violent act. The same device that had carried Mate’s authority as a doctor became a prop arranged around his own body, leaving investigators to ask who objected to his work and why.