Not giving up till the end, Troy Davis kept fighting till the last moment, till his execution on Wednesday night.

The Georgia man was executed 20 years after he was convicted of the fatal shooting of Mark Macphail, a police officer, despite a plea for clemency from people around the world.

Mark Macphail was shot in the chest and face when he sought to intervene in an argument in the car park of a Savannah takeaway.

Millions of people were convinced about his innocence and fought for him to be set free. But not a single court thought so.

Davis who was convicted at the age of 19 for the murder of 27-year-old Mark Macphail, told his relatives in the death chamber that he was not responsible for his 1989 death.

I am innocent. The incident that happened that night is not my fault. I did not have a gun. All I can ask ... is that you look deeper into this case so that you really can finally see the truth, the 42-year-old said, according to Sydney Morning Herald.

Thousands of supporters signed petitions on Davis' behalf including an ex-president and an ex-FBI director, liberals and conservatives.

According to his attorneys, seven out of nine key witnesses against him disputed all or parts of their testimony, but in vain. The state and federal judges repeatedly ruled against him -- three times on Wednesday alone.

The lethal injection was given at about 10:53 p.m. ( Georgia time) and Davis was declared dead 15 minutes later, at 11:08 p.m., after the Supreme Court rejected an eleventh-hour request for a stay.

Justice has been served for Officer Mark MacPhail and his family, state Attorney General Sam Olens announced in a statement.

There were no comments from the court regarding its decision on the stay that came more than three hours after the scheduled execution time.

Regardless of the fact that Davis is not alive anymore, he asked his family and friends to continue to fight this fight. He wants his innocence to be proved to the world and his family to be proud, even if he is not physically present to see it all himself.

His last words for the prison officials were, May God have mercy on your souls. May God bless your souls.

So how did MacPhail's family feel sitting in the death chamber, witnessing the execution that they had been waiting for years?

MacPhail's widow, Joan MacPhail-Harris, said that there was nothing to rejoice, but that it was a time for healing for all families.

I will grieve for the Davis family because now they're going to understand our pain and our hurt, she told Jackson in a telephonic interview. My prayers go out to them. I have been praying for them all these years. And I pray there will be some peace along the way for them, the report said.

When asked about Davis' claims of innocence, she said, He's been telling himself that for 22 years. You know how it is, he can talk himself into anything.

Davis' family members who witnessed the execution, did'nt talk to the reporters.

Davis' execution had been stopped three times since 2007, and on Wednesday, in his last hour, Davis turned down an offer for a special last meal as he met with friends, family and supporters.

Davis had offered to undergo a polygraph test and had the pardons officials agreed to it, he would have spent some time on Wednesday going through it, said his attorney Stephen Marsh.

Troy Davis has impacted the world, his sister Martina Correia said at a news conference. They say, 'I am Troy Davis,' in languages he can't speak.

Davis' supporters believe that if anyone has to take a look at the case even a bit closely, they will know that there are too many doubts and not enough reasons to execute him.

The U.S. Supreme Court had given Davis an unusual opportunity to prove his innocence in a lower court last year, though the high court itself did not hear the merits of the case.

In Davis' case, no gun, DNA evidence or surveillance footage was found to link Davis to the crime, moreover, the witnesses from the crime scene who had given their testimonies have recanted their accounts.

The case is doubtful to the extent that some people say that the man who was with Davis that night told people he is the one to have actually shot the officer.

Such incredibly flawed eyewitness testimony should never be the basis for an execution, Marsh said. To execute someone under these circumstances would be unconscionable.

On Wednesday, in Texas, white supremacist gang member Lawrence Russell Brewer was also put to death for the 1998 dragging death of a black man, James Byrd Jr.