LONDON (AP) — An alternative healer who advocated “slapping therapy” to treat a range of maladies was sentenced Friday to 10 years in prison for the death of a 71-year-old diabetic woman who stopped taking insulin during one of his workshops.

Hongchi Xiao, 61, was convicted of manslaughter by gross negligence for failing to get medical help for Danielle Carr-Gomm as she howled in pain and frothed at the mouth during the fourth day of a workshop in October 2016.

Xiao, of Cloudbreak, California, promoted paida lajin therapy, getting patients to slap themselves repeatedly to release “poisonous waste” from the body. The technique has its roots in Chinese medicine, but critics say it has no scientific basis and patients often end up with bruises, bleeding — or worse.

Carr-Gomm was one of two of Xiao’s patients who died.

He was extradited from Australia, where he had been convicted of manslaughter after a 6-year-old boy died when his parents withdrew his insulin medication after attending one of his workshops in Sydney.

“I consider you dangerous even though you do not share the characteristics of most other dangerous offenders,” Justice Robert Bright said during sentencing at Winchester Crown Court.

“You knew from late in the afternoon of day one of the fact that Danielle Carr-Gomm had stopped taking her insulin,” the judge said. “Furthermore, you made it clear to her you supported this.”

Bright said Xiao only made a “token effort” to get Carr-Gomm to take her insulin once it was too late and had shown no sign of remorse as he continued to promote paida lajin in prison.

Carr-Gomm was diagnosed with type 1 diabetes in 1999 and was desperate to find a cure that didn’t involve injecting herself with needles, her son, Matthew, said.

She sought out alternative treatments and had attended a previous workshop by Xiao in Bulgaria a few months before her death in which she also became seriously ill after ceasing her medication.

However, she recorded a video testimonial, calling Xiao a “messenger sent by God” who was “starting a revolution to put the power back in the hands of the people to cure themselves and to change the whole system of healthcare.”

Xiao had congratulated Carr-Gomm when she told other participants at the English retreat that she had stopped taking her insulin.

By day three, Carr-Gomm was “vomiting, tired and weak, and by the evening she was howling in pain and unable to respond to questions,” prosecutor Duncan Atkinson said.

A chef who wanted to call an ambulance said she deferred to those with holistic healing experience.

“Those who had received and accepted the defendant’s teachings misinterpreted Mrs. Carr-Gomm’s condition as a healing crisis,” Atkinson said.