The cemetery in the western Austrian town of Hall contains the remains of 220 people. Officials at the hospital told reporters that, while not all were believed to have been victims of a Nazi euthanasia campaign, evidence indicated that at least some could have been targets of the organized killings.
The Nazis described those killed - some physically or mentally handicapped, others homosexuals, Gypsies or others who did not fit Hitler's ideals - as "worthless lives."
Across Europe, 75,000 people, including 5,000 children, were killed for real or imagined mental, physical or social disabilities that did not fit Nazi pseudo-Aryan ideals. Hundreds of them were sent from psychiatric institute of the Hall hospital complex to the main killing site - a castle in the western Austrian town of Hartheim - where nearly 30,000 people were gassed to death or given fatal injections.
Although the organized euthanasia campaign was formally declared ended in 1941, individual hospitals in Austria and Germany continued killing people deemed deficient by starvation, medication and other methods, resulting in hundreds of victims.
Historian Oliver Seifert told reporters that investigations will focus on whether the Hall psychiatric institute in Hall was involved in such killings.
Deputy hospital director Christian Haring said in comments cited by the Austria Press Agency that suspicions were aroused in part by the fact that there was "a noticeable increase in deaths at the Hall institute." He said 30 people died in March 1945 alone, in the final stages of World War II.
He said that, while the existence of the cemetery had long been known, it was not considered to be connected to the Nazi killing campaign until the discovery of a list of those buried there while hospital archives were being moved.
The start of the investigations coincided with the planning for a construction project on the cemetery site. That has been suspended pending the end of investigations and the exhumation of the graves to establish the identities of the dead, how they were killed and attempts to contact relatives - a task that officials said would likely last two years.