A Sydney man who bashed a gay man to death after he revealed he had HIV, says he is haunted by what he did.
But the crown has questioned how he managed to keep these emotions "in check" throughout his trial.
Felipe Flores's battered body was discovered with his pants around his ankles in an area once coined "lovers' lane" in Woolloomooloo on September 2, 1991.
For years, the 27-year-old's death remained a mystery.
But after detectives from the unsolved homicide squad found DNA under Mr Flores's fingernails in 2008, Armstrong was arrested.
A jury then found Armstrong guilty of Mr Flores' murder in 2010, however, an appeal saw his conviction quashed.
Armstrong, who has also been convicted of rape, is now being sentenced for Mr Flores's manslaughter on the basis of provocation.
At a hearing on Thursday, the Supreme Court heard the pair had met at the nearby Exchange Hotel on Sydney's Oxford Street in the early hours of September 2.
They then went to "lovers lane" and had oral sex.
Armstrong told the court he became "very angry" when, after their sexual encounter, Mr Flores revealed he had HIV.
By this time, Armstrong said the infamous advertising campaign portraying the virus as the grim reaper had "terrified him".
He believed HIV was "a death sentence".
So when Mr Flores revealed his diagnosis, Armstrong said he picked up his shoe and started hitting him around the head. He then "squatted" on him.
Mr Flores's internal injuries were so severe his liver had almost been split in two.
But Armstrong said he never meant to kill Mr Flores.
Wiping away tears the former security guard said: "I have thought of nothing else since I found out that I was the cause of Mr Flores's death".
Crown prosecutor Ken McKay questioned this, saying when it was put to him during the trial that he attacked or killed Mr Flores, he denied it.
"You didn't cry about Mr Flores at trial," Mr McKay said.
Armstrong was convicted in 2010 of two counts of sexual intercourse without consent. His victim was a man.
The hearing continues.
