A former anaesthetist has been jailed for life for intentionally poisoning 30 patients, 12 of them fatally.

Frédéric Péchier, 53, was convicted Friday at the end of a four-month trial in the eastern city of Besançon.

In one of France's biggest ever medical malpractice cases, Péchier was found to have introduced chemicals like potassium chloride or adrenaline into the infusion bags of patients.

His youngest victim, a four-year-old child, survived two cardiac arrests during a routine tonsil surgery in 2016. The oldest victim was 89.

Prosecutors labeled him a Doctor Death, asserting that he brought shame upon the medical profession, stating: You are a poisoner, a murderer. You have turned this clinic into a graveyard.

The chemicals Péchier added triggered cardiac arrest or hemorrhaging in patients, which required emergency intervention in the operating theatre—a rescue he often provided himself to pose as a hero.

However, in the 12 cases resulting in fatalities, he was unable to intervene in time.

The prosecution claimed that he acted out of a grudge against fellow anaesthetists and tampered with infusion bags while not being the primary anaesthetist in most operations, allowing him to step in during emergencies.

Péchier was under investigation for eight years after a spike in cardiac arrests among patients at the clinics where he worked.

Alarm was raised in 2017 when excessive potassium chloride was discovered in an infusion bag linked to a patient who suffered a heart attack during surgery.

Over the years, investigators uncovered a pattern of suspicious events at the Saint-Vincent private clinic, where the rate of fatal heart attacks during anesthesia was disproportionately high.

They noted that the adverse events ceased while Péchier was briefly employed at another clinic, only to resume upon his return.

His first known victim, Sandra Simard, experienced a cardiac arrest during spine surgery but survived thanks to Péchier's intervention. However, tests revealed an alarming concentration of potassium in her infusion.

Throughout the 15-week trial, Péchier occasionally acknowledged the possibility of poisoning but denied intent, asserting, I have always upheld the Hippocratic oath.

He will serve a minimum of 22 years before eligibility for parole. His story resonates deeply as survivors express relief, hoping for a more secure future in medical care.