LONDON — A retired Austrian neurologist whose trial for alleged Nazi war crimes was adjourned indefinitely may have celebrated too soon.

Judge Karlheinz Seewald stopped the trial just 20 minutes after it started last week — after a psychiatrist testified that Heinrich Gross is suffering from dementia.

But Seewald is now believed to be having second thoughts after the 84-year-old Gross told a television interviewer that the state did not have enough evidence to try him for complicity in the murder of nine children at Vienna's Am Spiegelgrund Clinic during World War II.

The judge said it was "completely impossible to understand" how a man who was suffering from dementia could have given such an interview.

At the same time, prosecutor Michael Klackl called for new tests to be performed on Gross, possibly by a German expert.

Gross' postwar job as an expert psychological witness in Vienna's courts until 1998 had given him too many ties to Austrian psychologists, Klackl suggested.

At last week's abbreviated trial, Gross appeared to be frail and confused.

"Can you understand me?" the judge asked.

"Badly," replied Gross.

"Can you understand anything?" asked the judge.

"A little," replied Gross.

The judge then told the court that the psychiatric report showed that Gross was suffering from a "disturbance of the central nervous system caused by dementia and Parkinson's syndrome."

Declaring that "Gross' ability to understand what is going on is limited," Seewald announced an indefinite postponement of the trial, noting that Gross "cannot fully make use of his rights as a defendant."

At the time, it was considered unlikely that the trial — which would have been the first significant war crimes case in Austria since 1975 — would ever resume.

Gross, who was known at the wartime clinic as "The Scythe" — a reference to the Grim Reaper — was tried and convicted on a single count of manslaughter in 1950. He was sentenced to two years in jail, but the verdict and sentence were overturned by Austria's Supreme Court, which ordered a retrial.

It is believed that if Gross were to be convicted, Austrian courts would likely face a stream of appeals by people who were convicted on the evidence that Gross had provided as an expert witness.