They deployed Raman spectroscopy, in which refracted light from a laser beam gives chemical clues about a sample.
This showed the presence of hemoglobin and fibrin, which are key components in blood clotting, at the arrow wound on Ötzi's back.
"Because fibrin is present in fresh wounds and then degrades, the theory that Oetzi died straight after he had been injured by the arrow, as had once been mooted, and not some days after, can no longer be upheld," Zink said.
Ötzi's remains were discovered by two German hikers in September 1991 in the Ötzal Alps in South Tyrol, northern Italy, 3,210 meters (10,500 feet) above sea level.
Scientists have used high-tech, non-invasive diagnostics and genomic sequencing to penetrate his mysterious past.
These efforts have determined Ötzi died around the age of 45, was about 1.60 meters (five foot, three inches) tall and weighed 50 kilos (110 pounds).
He suffered a violent death, with an arrow severing a major blood vessel between the rib cage and the left scapula, as well as a laceration on the hand.