ROME—Dr. Carlo Mosca’s online patient reviews describe a loving “humanitarian” who saved countless lives before the coronavirus pandemic struck Italy. Patients and their families lavished praise on the loving father, whose hospital in Brescia in northern Italy was one of the hardest hit during the first wave of the pandemic last March.

Something clearly changed in Mosca as the pandemic raged on. The 47-year-old was arrested on double homicide charges this week, accused of killing weak COVID patients and doctoring their medical records in order to free up beds for other patients. Mosca describes the allegations as “baseless” claiming that the overwhelmed health care system is the reason the patients died.

During the first months of the pandemic, Italian doctors were faced with horrifying decisions in deciding who to give respirators and other supplies to, often deciding who lives or dies based on their chance of survival, essentially letting the weak die due to lack of treatment. But what Mosca is accused of is taking it one step further and killing the patients himself.

Two patients who died under Mosca’s care, Natale Bassi, 61, and Angelo Paletti, 80, were exhumed last month as the prosecution built the case against the primary care physician using text messages among nurses who watched the once-loving physician transform from Dr. Jekyll into a sinister Mr. Hyde—although one very likely overwhelmed by the sheer magnitude of the human tragedy around him.

The investigating magistrate in the case has suggested that Mosca was the “victim in the throes of extreme stress originating from having to face the growing influx of COVID cases,” according to the court documents. “The replication of the extreme conditions that led to his crimes made it probable that he resolved to administer prohibited drugs to the most serious patients in order to speed up their death, thereby falsifying the data contained in the relative medical records.” Simply withholding treatment would have allowed the patients to linger for weeks or months. By injecting them, the prosecutor wrote, Mosca could more quickly free up the much-needed beds.

Authorities are now combing through records of all of Mosca’s dead patients to search for anomalies in their treatment and deaths. They do not rule out exhuming further bodies, although the majority of the people who died during the height of the first wave of the pandemic were cremated.

As Mosca’s hospital became overwhelmed and more than 600 COVID patients were suddenly under his care, nurses say he started directing them to inject lethal doses of Succinylcholine and Propofol, which are often used when intubating patients, into COVID sufferers who were never meant to be intubated. Using the drugs on non-intubated patients causes them to suffocate, according to the court documents. During the months of March and April, before a nurse confronted Mosca and threatened to report him, orders for both drugs grew by 70 percent, according to court documents seen by The Daily Beast.

As things grew more frantic, the nurses started exchanging worrying messages that now form the prosecution’s case, and at least one confronted him about his state of mind. “Did he ask you to administer the drugs without intubating them?” one nurse wrote. “I'm not killing patients just because he wants to free up the beds. This is crazy,” wrote another.

When nurses started refusing Mosca’s orders, he allegedly started injecting the patients personally, asking the nurses to leave him alone with the patients. Prosecutors say he also wrote false terminal diagnoses on the patients’ charts, giving them a more believable cause of death.

Mosca, who has been put on leave from his hospital, is under house arrest until his trial begins this spring.