Scientists say they are no closer to knowing whether a skull is that of Austrian composer Wolfgang Amadeus Mozart, despite months of tests.
The skull has been kept in a museum for over 100 years
They admitted in a TV documentary on Sunday they cannot say for certain whether the skull is that of Mozart.
"For the time being, the mystery of the skull is even bigger," said researcher Dr Walther Parson.
The investigation comes in the lead-up to the 250th anniversary of the birth of the composer.
Mozart, widely regarded as one of the most influential classical composers, died in 1791 at age 35 and was buried in a pauper's grave at Vienna's St. Mark's Cemetery. The exact position of his final resting place was not known.
The skull which is being tested has, since 1902, been kept by the International Mozarteum Foundation in Salzburg, where Mozart was born.
Austria is preparing for the 250th anniversary of Mozart's birth
Joint investigations by the Institute for Forensic Medicine in Innsbruck and the US Armed Forces DNA Identification Laboratory in Rockville, Maryland were carried out on the skull.
They studied two teeth taken from the skull compared to thigh bones taken from skeletons in the Mozart family grave at Salzburg's St Sebastian Cemetery.
The remains were thought to be of Mozart's maternal grandmother and a niece. But further DNA testing showed none of the skeletons were related, which made it impossible to prove the skull's identity.
"The dead took their secrets to the grave," the documentary said.