A young man, who was in a coma for nearly four years in Germany after his work lunch was poisoned by a colleague, has died, German media report.
The 26-year-old ingested lead acetate and mercury after it was sprinkled on his sandwiches, resulting in severe brain damage.
Two of his colleagues were also targeted and suffered kidney damage.
A man, named only as Klaus O, was found guilty of attempted murder last year and sentenced to life in prison.
On Thursday, state prosecutor Veit Walter said a new trial could be ordered by Germany's Supreme Court now that one of the victims had lost his life, the Bild newspaper reported.
The death was confirmed by a court in the city of Bielefeld, about 350km (218 miles) west of the German capital, Berlin.
The case came to light in 2018 after a colleague at a metal fittings company in the town of Schloss Holte-Stukenbrock, in north-western Germany, noticed a white powder on his lunch.
Video surveillance cameras were later installed at the workplace, which captured Klaus O placing the substance on his colleagues' sandwiches.
Tests identified it as lead acetate and mercury, almost tasteless substances that if ingested could lead to serious organ damage.
Further searches at Klaus O's home uncovered mercury, lead and cadmium.
Following his trial in March 2019, a judge ruled that Klaus O would not be eligible to have his sentence reduced because he was a "danger to the general public".
A psychologist told the trial at the time that Klaus O "came across like a researcher who was trying to see how different substances affected rabbits".