At first, scientists believed that Ötzi was caught in a heavy snowfall, fell asleep, and froze to death. They concluded this because there were no signs of predator attacks.
Theory 1: Discarded. The first theory was put to rest in June 2001 when the Iceman was x-rayed by a different team of scientists (in Bolzano). They discovered that he had an arrowhead buried in his left shoulder.
Theory 2: Ötzi was shot accidentally
According to author Brenda Fowler, Dr. Annaluisa Pedrotti (University of Trento) speculated that the Iceman may have been shot by a hunter who buried Ötzi immediately.
Theory 2: Discarded. Studies suggested that the Iceman was a victim of homicide.
Theory 3: Ötzi was a victim of homicide
This theory says that Ötzi was a shepherd who was killed by another shepherd who wanted a larger flock of animals.
A study published in early 2009 suggested that the Iceman was injured in a brawl (the deep gash in his hand) a few days before he was killed by the arrow. They theorize that he fled from his village in a hurry--as shown by his unfinished arrows
Theory 3: Accepted. No one doubts that the Iceman was a victim of homicide at this point.
Theory 4: Ötzi was assassinated
This theory says Ötzi may well have been a shaman (religious man) and a highly respected member of his group. People killed Otzi to takeover his power role in their society. Leitner believes Ötzi was a shaman because of the possessions he had with him, in particular the copper axe which was not a common object.
Leitner also believes that the attackers kept at a distance during their attack, perhaps because they were afraid of the shaman and what he might do. By killing him in the mountains, well out of sight, his attackers may have hoped that his death (or disappearance) was seen as an accident. Perhaps that is why his tools and weapons were left with the body. Had they taken them, others who knew them would have wondered why they had these items.
Ötzi was killed at a lower altitude, carried up the mountain, and placed on a burial platform of stones. This platform was some 20 feet uphill from the place where Ötzi's body was found in 1991. Over the centuries, as the ice of the glacier occasionally thawed, his body was carried downhill in the melting water and came to rest where it was eventually found. "A careful study of all the located artifacts...points strongly towards the scene as one of a ceremonial burial – not a casual tragedy”.
However, while other scientists agree that the Iceman's body was moved slightly as the ice thawed, they do not believe that he died elsewhere or that the stones formed a burial platform. According to biological anthropologist "Ötzi probably died in the mountains alone and close to where he suffered a fatal injury.... The Iceman’s joints and spine display no dislocations that would have resulted from a downhill slide. Intact blood clots in his arrow wound would show damage if the body had been carted up the mountain...."