BRUSSELS (AP) — A Belgian court on Friday has acquitted three doctors of charges of manslaughter by poison in a case that has been seen as a key test of Belgium's euthanasia laws.

The three doctors were involved in the euthanasia of a 38-year-old patient, Tine Nys, who suffered with mental problems and died in 2010.

Her family took the case to court, arguing that the euthanasia should never have happened, claiming her mental state was not hopeless and treatment was still possible.

Nys had struggled with psychiatric problems for years and had attempted suicide several times.

“This is such a relief," psychiatrist Lieve Thienpont, one of the acquitted doctors, told VRT network.

Belgium is among a few countries that allow doctors to kill patients at their request, and one of two that allow it for people with a mental illness.

Out of about 2,000 euthanasia cases a year in Belgium, very few are permitted for psychological issues. The criminal complaint by the family was only granted on appeal after it was first rejected by a lower court.