An ophthalmologist in his 40s from Pusan National University Hospital died in his home early Sunday morning, according to the Busan Metropolitan Police Agency on Monday.

On Sunday at 4:30 a.m., police officials received a call that the doctor was found unconscious in his home. When emergency medical services reached the doctor’s home, he did not have a pulse nor was he breathing, according to police officials. The doctor was immediately taken to the Inje University Haeundae Paik Hospital near his home, where he was pronounced dead.

According to the police, the exact cause of the doctor’s death is yet to be confirmed, though it “appears to have been caused by heart failure due to a stroke.”

Following the doctor’s death, several speculations were raised in an online community with doctors as to whether it was due to overwork. According to local media reports, since several trainee doctors staged a walkout last month, the doctor had frequently expressed that he felt fatigued after taking on ambulatory care, overnight duties and emergency patient surgeries.

According to professor Oh Sae-ock from the Medical Professors Association of Pusan National University, it is “possible” that the doctor’s death is related to overwork, though it has not been officially confirmed.

“For a month, medical school professors at university hospitals have taken on duties that are normally done by trainee doctors while also doing their own work,” said Oh.

Before the joint strike by the trainee doctors, nine professors were on duty at Pusan National University Hospital’s department of ophthalmology, including 10 trainee doctors who would assist the professors during surgeries and take the overnight shifts. However, all 10 trainee doctors left to participate in the joint strike on Feb. 20.

When asked whether the doctor had died of overwork, the police officials also commented that it could not be confirmed.

“The police plan to conduct investigations with the doctor’s family members and colleagues and conduct an autopsy to determine the exact cause of his death,” said the police. The police will also work closely with the Pusan National University Hospital to check how much the doctor’s duties had increased over the last month.