An investigation into the work of discredited South Korean cloning scientist Hwang Woo-suk has found further fabrications in his research.
The investigation's findings have stunned many South Koreans
His 2004 landmark claim to have taken stem cells from a cloned human embryo was false, a panel has concluded.
But the investigators, who last month rejected other research by the scientist, have accepted that he did create the world's first cloned dog.
Dr Hwang has admitted errors, but claims his work was sabotaged.
State prosecutors are now expected to look into the case.
BBC Seoul correspondent Charles Scanlon says the conclusion of the university's investigation completes the disgrace of Dr Hwang, who was South Korea's most celebrated scientist.
Dr Hwang claimed in a 2004 paper published in the US journal Science that his team had created 30 cloned human embryos and produced a line of stem cells from one of them.
The achievement was judged to be a major scientific breakthrough in the search for cures for a range of degenerative diseases including diabetes and Parkinson's.
Dr Hwang led the project that created the cloned dog Snuppy
But the nine-member Seoul National University panel, which spent a month examining Dr Hwang's work, said in a statement on Tuesday: "The 2004 paper was written on fabricated data to show that the stem cells match the DNA of the provider although they didn't."
The South Korean team "did not have any proof to show that cloned embryonic stem cells were ever created," the panel concluded.
The same panel revealed last month that a later paper which seemed to take Dr Hwang's cloning work even further was also faked.
In the May 2005 paper, also published by Science, Dr Hwang claimed to have developed stem cells that were tailored to individual patients.
Feb 2004 Hwang Woo-suk's team declare they have created 30 cloned human embryos and extracted stem cells
May 2005 Team says it has made stem cell lines from skin cells of 11 people
Nov 2005 Hwang apologises for using eggs from his own researchers
15 Dec 2005 A colleague claims stem cell research was faked
23 Dec 2005 Academic panel finds results of May 2005 research were fabricated
10 Jan 2006 Panel finds 2004 work was also faked
"We concluded that Professor Hwang's team did not have patient-specific stem cell lines, and did not have any scientific basis that the team made them," the panel said.
Science has said it will retract both the 2004 and the 2005 papers.
The university panel did not say what sanctions would be imposed on Dr Hwang as a result of its findings, but said the penalty had to be "severe".
It did not address Dr Hwang's claim that researchers in his laboratory could have maliciously switched some of his stem cells to give erroneous results.
State prosecutors are now expected to launch their own investigation into possible fraud, and the misappropriation of public funds.
"We will take over relevant evidence from the Seoul National University and decide on who will take up this case," Park Young-Soo, from the prosecutor general's office, told the French news agency AFP on Tuesday.
Professor Colin Blakemore, chief executive of the UK Medical Research Council, said people should not use Dr Hwang's case to call for an end to stem cell research.
"It would be very sad if the clearly unethical behaviour of Dr Hwang were in any way confused with the ethical issues of whether it's right to use human embryos to develop treatments for serious illness," he said.
Dog was cloned
The shaming of Dr Hwang has come as a profound shock to South Koreans, many of whom saw the cloning pioneer as a national hero.
Some analysts are describing his fall from grace as one of the biggest cases of scientific fraud in recent history.
Dr Hwang has not made any public appearances since saying he would resign his faculty position last month, and his current whereabouts are unknown.
But there was some positive news for the beleaguered scientist on Tuesday.
The university panel ruled that an experiment last year in which Dr Hwang's team claimed to have cloned a dog was genuine.
A three-year-old Afghan hound called Snuppy - short for Seoul National University puppy - was genetically identical to his father according to DNA tests.