Wrongful execution is a miscarriage of justice occurring when an innocent person is put to death by capital punishment. Cases of wrongful execution are cited as an argument by opponents of capital punishment, while proponents say that the argument of innocence concerns the credibility of the justice system as a whole and does not solely undermine the use of the death penalty. A variety of individuals are claimed to have been innocent victims of the death penalty. Newly available DNA evidence has allowed the exoneration and release of more than 20 death-row inmates since 1992 in the United States, but DNA evidence is available in only a fraction of capital cases. At least 190 people who were sentenced to death in the United States have been exonerated and released since 1973, with official misconduct and perjury/false accusation the leading causes of their wrongful convictions. The Death Penalty Information Center (U.S.) has published a partial listing of wrongful executions that, as of the end of 2020, identified 20 death-row prisoners who were "executed but possibly innocent". Judicial murder is a type of wrongful execution. Specific examples Australia Colin Campbell Ross was hanged in Melbourne in 1922 for the murder of 12-year-old Alma Tirtschke the previous year in what became known as the Gun Alley Murder. The case was re-examined in the 1990s using modern techniques and Ross was eventually pardoned in 2008, by which time capital punishment in Australia had been abolished in all jurisdictions. Ronald Ryan was the last person executed in Australia. His execution took place on 3 February 1967. He and a fellow inmate, Peter John Walker, attempted to escape from Pentridge Prison on 19 December 1965, when prison guard George Hodgson was shot and killed. Multiple witnesses swore that they saw Ryan fire the shot that killed Hodgson, so he was found guilty. The true identity of the shooter is in contention as two other guards admitted to firing several shots, and in 2007, Peter John Walker said that it would have been impossible for Ryan to have shot the guard as his rifle had jammed. People's Republic of China Wei Qing'an (, born 1961) was a Chinese citizen who was executed for the rape of Kun Liu, a woman who had disappeared. The execution was carried out on 3 May 1984 by the Intermediate People's Court. In the next month, Tian Yuxiu () was arrested and