The killers were executed, but questions remain over whether justice was done.

After United States death row inmate Clayton Lockett on Wednesday took more than 40 minutes to die after an experimental lethal injection, here's a look at other execution cases which have attracted attention.

Napoleon Beazley (2002)
Beazley was 17 when he was arrested for the murder of 63-year-old businessman John Luttig in Texas. Beazley shot Luttig in his garage on April 19, 1994. He also fired at Luttig's wife but she survived the attack. He was convicted and sentenced to death. Before his execution date the Supreme Court began reviewing the law on sentencing juveniles to death, but Beazley was put to death on May 28. In 2005, the Supreme Court ruled that the execution of juveniles was cruel and unusual punishment and therefore illegal under the United States constitution. Beazley was one of the last juveniles to be executed in the US.

Cameron Todd Willingham (2004)
Willingham was convicted of murdering his three daughters in a house fire in Texas in 1991. Willingham refused to plead guilty at his trial despite the fact that this would spare him from the death penalty. During and after his trial scepticism began to grow over the evidence that the fire was caused deliberately. A fire inspector reviewed the case and said that he did not believe the evidence pointed fairly towards arson. Despite this Willingham was executed on February 17, 2004. After his death concerns over the evidence continued to grow leading to a report in the New Yorker quoting various experts as saying the evidence for arson was unconvincing and had information been available before his death Willingham would have been acquitted. The report led to a formal review of the case and in 2009 the Texas Forensic Science Commission said the fire marshal's declaration of arson was unfounded.

Kelsey Patterson (2004)
Patterson was convicted of the murder of Louis Oates, 63 and Dorothy Harris, 41. On August 25, 1992, Patterson walked behind Oates at his workplace in Palestine, Texas, and shot him in the back of the head. Patterson then left only to return soon after to kill Harris, when he heard her screams at discovering Oates' body. Patterson had been involved with two non-fatal shootings before this event, but he was diagnosed with paranoid schizophrenia so was deemed unfit to stand trial. After the murders of Oates and Harris, psychiatrists found him to be suffering from schizophrenia and under the delusion that he was being controlled by aliens. Despite this Patterson stood trial was convicted and sentenced to death. The Texas board of Pardons and Paroles advised that Patterson's sentence should be reduced from death to life imprisonment on the grounds of mental illness. Texas Governor Rick Perry overruled this saying "This defendant is a very violent individual - in the interest of justice and public safety, I am denying the defendant's request for clemency". Patterson was executed in May 2004.


Teresa Lewis (2010)
Lewis was the first woman to be executed by lethal injection in Virginia. She was found guilty of murdering her husband and stepson in October 2002 to claim life insurance. Lewis had an IQ of 72, two points above the mark that would have deemed her intellectually disabled and therefore would be treated substantially more leniently. Despite campaigns to stop the execution because of this, Lewis was executed on September 23, 2010.

Humberto Leal Garcia (2011)
Leal was convicted of the rape, kidnap, torture and murder of 16-year-old Adria Sauceda in 1994. Leal was a Mexican citizen but on his arrest he was not told of his right to contact the Mexican consulate by police. Leal was not the only Mexican inmate in an American prison to have been denied this right. The International Court in The Hague ruled that the inmates had been denied their rights under the Vienna Convention. The US Supreme Court said the decision by the international court was binding, but Congress had to pass a law allowing cases to be reviewed. As Leal's execution date approached President Barack Obama asked the Supreme Court to allow clemency to preserve America's standing on the world stage. The Supreme Court rejected the request, saying Congress had had enough time to pass a law. Leal was executed by lethal injection on July 7, 2011.

Troy Davis (2011)
Davis was arrested and convicted of murdering off-duty police officer Mark MacPhail in Georgia on August 19, 1989. MacPhail was working as a security guard when he went to the aid of a homeless man who was being beaten in a nearby parking area. MacPhail was then shot to death. Davis was convicted of the murder but claimed he was innocent. In appeals, the defence said the absence of a murder weapon meant Davis could not fairly be deemed guilty, and provided affidavits in which seven witnesses recanted their statements about the night of the murder. The case became high profile, and support for Davis came from celebrities, the National Association for the Advancement of Coloured People, Amnesty International and former President Jimmy Carter. Nearly one million people signed a petition to the Georgia Board of Pardons and Paroles to grant clemency. All the appeals and pleas failed, and Troy Davis was put to death on September 21, 2011.

Dennis McGuire (2014)
McGuire was convicted of the 1989 rape and murder of a pregnant woman and was sentenced to death. On January 16 this year, McGuire was executed by lethal injection in Ohio with a combination of drugs that had not before been used in the state, midazolam and hydromorphine. The drug cocktail is intended to sedate the inmate, slow his breathing, prevent pain and bring on a calm and quick death. McGuire took 26 minutes to die and could be seen by his family apparently writhing in pain. Doctors have said the spasms were not pain and that McGuire was unconscious. The case prompted the state of Ohio to say this week that it would increase the dosage of the drugs to ensure an easier passing for the next execution.

Joseph Franklin (1977)
The execution of the white supremacist was opposed by Hustler magazine publisher Larry Flynt, who was crippled in a previous shooting by Franklin. Flynt went to court to demand the name of the anaesthetist who presided over Franklin's execution. Franklin, who was executed for killing Gerald Gordon outside a St Louis, Missouri synagogue in 1977, admitted shooting Flynt in an assassination attempt which left the porn mogul in a wheelchair. Despite Flynt's opposition, Franklin was executed last November. But the publisher has maintained his legal fight with the backing of the American Civil Liberties Union. Court papers say Flynt is challenging the "secrecy surrounding Missouri's execution process" accusing the state of using "unsavoury methods to secure and maintain execution drugs" and hide the information from the public. The publisher wants the court to release the name of the anaesthetist to verify whether he was a member of the American Board of Anesthesiology, which says its members should not participate in executions. According to the writ, the board could revoke the licence of a member who does preside over a lethal injection. Flynt has accused Missouri of lying about the anaesthetist's legal standing and violating the US constitution's eighth amendment which outlaws cruel and unusual punishment.

Ricky Ray Rector (1992)
Ricky Ray Rector was executed in Arkansas on January 24, 1992. His execution, the third since the reinstatement of the death penalty in the state two years earlier, attracted notoriety because of the role of Bill Clinton, who was Governor of Arkansas as well as a presidential candidate at the time. Rector was sentenced to death for shooting Arthur Criswell in the throat and forehead after being Criswell denied him entry to a party in Conway, Arkansas. Rector then killed Robert Martin, a police officer sent to arrest him. Rector then shot himself in the head, effectively administering a self-lobotomy. At his trial, lawyers said he was unfit to plead. After the death sentence, Rector's legal team made a plea for clemency. Other inmates at the prison in which he was being held said the killer would bark, howl and laugh uncontrollably in his cell. The final decision on whether the execution should go ahead rested with Clinton. Four years earlier Michael Dukakis, the Democrat candidate, had lost the 1988 presidential election over his tepid handling of a death penalty question in a televised debate. Determined to show that he was "tough on crime", Clinton not only rejected the clemency plea but flew to Arkansas to preside over the execution, though this was not legally required.Telegraph Group Ltd