Raj Theekoy has asked the Harte family to forgive him for not helping the 27-year-old as she was being attacked in her hotel room after hearing her cries for help.
The Irish woman was on honeymoon in Mauritius when she was found strangled to death.
“Tell John McAreavey I am sorry, tell her father I am sorry,” he told the Irish Mail on Sunday. “I hear her screaming ... it goes over and over in my head. What I should have done, what I could have done ... what I didn't do. My conscience is not clear.”
Hotel employees Avinash Treebhoowoon and Sandip Moneea are charged with the Irish woman’s death. Authorities claim the pair killed Harte after she came into the room for a snack and interrupted a robbery.
Theekoy is the prosecution’s trump card in the trial against Harte’s alleged killers, which will take place this week.
Originally, Theekoy was charged with conspiracy to commit murder, but after his decision to testify against his co-workers for the prosecution, the charges were dropped.
“It hasn't been easy,” he said. “But I am innocent. I regret not doing something, yes, but I was just walking by and going about my business. Then I wasn't sure if I could interfere. Looking back now, maybe I should have. I had only started working at Legends four months before and room 1025 wasn't my area. Maybe I was in the wrong place at the wrong time.”
Theekoy says he saw the two outside Harte’s room in an agitated state and went over to see what was happening. Under instruction not to reveal what was said outside the room, Theekoy told the Mail on Sunday that he was able to deduce that Harte was deceased.
“I did not go inside the room and I did not see the body but I knew that it was too late. I knew at that point that she was dead. I know what happened to her… how she died.
“I can't say any more. I am scared to say any more. I was frightened then and I am frightened now. I have something to say in court when the time comes.”
Theekoy denies that he was in any way influenced to give this testimony and that his only involvement in the whole affair was being caught on a CCTV camera outside Harte’s talking to the two suspects.
On Monday, a preliminary hearing will take place in Mauritius before the case is expected to move to the High Court.