Troy Davis supporters who are outraged at the death row inmate's execution are asking why is that defendants like Casey Anthony and Charles Manson are still alive, the Christian Post reported.

Davis was pronounced dead at 11:08 p.m. on Wednesday after Georgia officials executed him by lethal injection. He was put to death for the 1989 murder of police officer Mark MacPhail, and convicted in 1991.

There is much controversy surrounding Davis's case because there have been questions raised regarding the reliability of eyewitnesses. Nine people identified Davis as the one who pulled the trigger that killed the cop. Since the 1991 trial, seven of those witnesses have since recanted their stories saying police forced them into pointing out Davis as the person who is guilty of the murder.

Police never found forensic evidence and Davis was convicted largely on eyewitness testimony.

The Christian Post reported that tweeters have been weighing in on the case.

Casey Anthony gets a book deal, while #TroyDavis got a last meal. Charles Manson is still alive, and an innocent man just died. #RIPTROYDAVIS, one wrote, according to the Post.

#TroyDavis is dead while 'CHARLES MANSON' is still 'Alive' in prison. I'm done! another wrote.

Casey Anthony

Anthony, 25, was released from a Florida jail in July after being acquitted of murdering her 2-year-old daughter Caylee. She is currently serving probation for check fraud in Florida. Prosecutors argued that Anthony smothered the 2-year-old with duct tape before driving around with the remains for several days and dumping the body in woods near the family home.

Anthony has reportedly told investigators that a nanny took the little girl. However, there was no nanny.

Charles Manson

Mason is a criminal found guilty of conspiracy to commit the murder of actress Sharon Tate and several other victims in the 1970s. His death sentence was reportedly automatically commuted to life imprisonment when a 1972 decision by the Supreme Court of California temporarily removed the state's death penalty.

There are some tweeters who thought such a comparison is unfair.

Is Charles Manson evil and responsible for deaths? Yes. Did he commit murder? No, morons. #applesandoranges, one wrote in response.

Now they're comparing Troy Davis to Charles Manson...They're obviously not aware that Manson NEVER killed anyone. Get the facts, another wrote, according to the Post.