BERLIN: A German doctor went on trial Monday accused of killing 15 patients with lethal injections and acting as “master of life and death” over those in his care.

The 40-year-old palliative care specialist, named by German media as Johannes M., is alleged to have killed 12 women and three men between September 2021 and July 2024 while working in Berlin.

The doctor is accused of injecting the victims, aged between 25 and 94, with deadly cocktails of sedatives and in some cases setting fire to their homes in a bid to cover up his crimes.

The accused had “visited his patients under the pretext of providing medical care,” prosecutor Philipp Meyhoefer said at the opening of the trial at the state court in Berlin.

Johannes M. had organized “home visits, already with the intention of killing” and exploited his patients’ trust in him as a doctor, Meyhoefer said.

“He acted with disregard for life... and behaved as the master of life and death.”

A co-worker first raised the alarm over Johannes M. last July after becoming suspicious that so many of his patients had died in fires, according to Die Zeit newspaper.

He was arrested in August, with prosecutors initially linking him to four deaths.

But subsequent investigations uncovered a host of other suspicious cases, and in April prosecutors charged Johannes M. with 15 counts of murder.

A further 96 cases were still being investigated, a prosecution spokesman said, including the death of Johannes M.’s mother-in-law.

She had been suffering from cancer and mysteriously died the same weekend that Johannes M. and his wife went to visit her in Poland in early 2024, according to media reports.

The suspect reportedly trained as a radiologist and a general practitioner before going on to specialize in palliative care.

According to Die Zeit, he submitted a doctoral thesis in 2013 looking into the motives behind a series of killings in Frankfurt, which opened with the words “Why do people kill?”

In the charges brought against Johannes M., prosecutors said the doctor had “administered an anesthetic and a muscle relaxant to his patients... without their knowledge or consent.”

The relaxant “paralyzed the respiratory muscles, leading to respiratory arrest and death within minutes.”

In five cases, Johannes M. allegedly set fire to the victims’ apartments after administering the injections.

On one occasion, he is accused of murdering two patients on the same day.

On the morning of July 8, 2024, he allegedly killed a 75-year-old man at his home in the Berlin district of Kreuzberg.

“A few hours later” he is said to have struck again, killing a 76-year-old woman in the neighboring Neukoelln district.

Prosecutors say he started a fire in the woman’s apartment, but it went out.

“When he realized this, he allegedly informed a relative of the woman and claimed that he was standing in front of her flat and that nobody was answering the doorbell,” prosecutors said.

In another case, Johannes M. “falsely claimed to have already begun resuscitation efforts” on a 56-year-old victim, who was initially kept alive by rescuers but died three days later in hospital.

Prosecutors said he had “no motive beyond killing” and are seeking a life sentence.

The case recalls that of notorious German nurse Niels Hoegel, who was handed a life sentence in 2019 for murdering 85 patients.

Hoegel, believed to be modern Germany’s most prolific serial killer, murdered hospital patients with lethal injections between 2000 and 2005, before he was eventually caught in the act.

More recently, a 27-year-old nurse was given a life sentence in 2023 for murdering two patients by deliberately administering unprescribed drugs.

In March, another nurse went on trial in Aachen accused of injecting 26 patients with large doses of sedatives or painkillers, resulting in nine deaths.

Last week, German police revealed they are investigating another doctor suspected of killing several mainly elderly patients.

Investigators are “reviewing” deaths linked to the doctor from the town of Pinneberg in northern Germany, just outside Hamburg, police and prosecutors said.