Zhang Xiaojun, also 38, died on April 21, 2011. According to an interview Jia did with China Central Television, she had repeatedly asked him to end her life. "That day (in April), she cried and said she will never be cured, even after we had spent all our money," he said.

The court that heard the case has yet to hand down a verdict.

Jia could well receive a similar punishment to Deng Mingjian, a migrant worker in Guangzhou who in May was sentenced to three years in prison, suspended for four years, after he admitted assisting in his mother's suicide.

"She was in great pain," Deng told China Daily, adding that he had cared for his mother for two decades because she had rheumatoid arthritis. "That day, she grabbed me so hard. Seeing her in agony, I had to say yes."

He said he bought her pesticide and helped her drink it. "My mind just went blank as I did it," he recalled.

China does not have any official data on incidences of euthanasia nationwide, or how many people use it as a defense in court. However, Hong Daode, a professor at China University of Political Science and Law, said he has noticed an increasing number of cases.

He said their actions can "absolutely be classed as intentional homicide" but explained that judges may give more lenient sentences - three to 10 years - due to mitigating circumstances.

However, as Tang Chengkui, the attorney that defended Deng, pointed out: "Even if someone says theirs was an act of mercy, it's extremely hard for a court to rule out the possibility of murder."

A merciful law

Qiu Renzong, an expert in medical ethics and an advocate of legal euthanasia, said legalizing euthanasia can help people living in pain find peace and prevent murder.

He suggested the government pilot a system at selected hospitals in which patients can be assessed for their suitability and receive professional help.

"These (trials for so-called mercy killings) are happening purely because there is no legislation that decriminalizes assisted suicide and sets strict conditions on how it can be conducted," said Qiu, a researcher at the Chinese Academy of Social Sciences. "I suggest letting a few hospitals try it, so they can assess patients properly. Otherwise it's possible that some people will take advantage and attempt to get away with murder."

To qualify, he said a person must have a terminal illness and be in "unbearable pain" that cannot be alleviated by medication. There must also be an official record showing the person has repeatedly insisted on euthanasia. "Any application would have to be appraised by a medical professional and conducted in a painless way."

Zhai Xiaomei, a professor of medical ethics at Peking Union Medical College, agreed: "This is a very serious matter, so the prerequisites need to be designed very carefully."

In a petition circulated online by Li Yan in 2007, she said euthanasia does not only free the terminally ill, but also their families.

"The torture for the family taking care of the patient is no less than that of the patient," she wrote. "Most families can't afford the huge medical costs and may fall into debt, even though there is no cure for the patient's illness."