There were no DNA traces from the two men accused of murdering Michaela McAreavey found on her body or at the crime scene in Mauritius, a court has heard.
A forensic expert from England told the trial of the two hotel workers that their genetic material was not identified on a range of swabs taken from the tragic honeymooner or on samples recovered from the hotel room in the island's luxury Legends Hotel where she was found strangled last January.
Susan Woodroffe from Cellmark Forensic Services was also asked to examine whether the DNA of defendants Avinash Treebhoowoon and Sandip Moneea and two other original suspects in the case - fellow Legends employees Raj Theekoy and Dassen Naraynen - was present on the samples.
While Ms Woodroffe found no matches from the four men on swabs taken from the victim's body, she did identify a potential match with Naraynen on a key card for the room.
Naraynen is facing a larceny charge in connection with the case in separate court proceedings.
But in relation to samples taken from Mrs McAreavey's neck, feet and fingernails, the forensic expert told the criminal court in Port Louis:
"There is no specific indication that any of Raj Theekoy, Sandip Moneea, Avinash Treebhoowoon or Dassen Naraynen have contributed to the results obtained."
Genetic material other than belonging to Mrs McAreavey and her husband John was found on a sample taken from her head, but the expert said if it was from a sole contributor then all four men could be ruled out.
Hotel workers Treebhoowoon, 30, and Moneea, 42, deny the premeditated murder of the teacher, who was the daughter of Tyrone gaelic football boss Mickey Harte.
Mrs McAreavey was found dead in her hotel room shortly after lunching with her husband John by the pool.
The prosecution claim she returned to her room to fetch biscuits for her tea and caught the accused stealing in her room.
Earlier in court a policeman remained silent when asked what he did with Treebhoowoon the morning after the crime.
Treebhoowoon alleges that police beat a confession out of him in the wake of the honeymooner's death.
Constable Hans Rouwin Seevathian of the Major Crime Investigation Team was questioned by a defence solicitor about what he and his team did with his client in a two-and-a-half hour period between them arriving at Legends Hotel and Treebhoowoon making a statement in a local police station.
The court fell silent as the officer did not offer an answer.
After a few moments judge Mr Justice Prithviraj Fecknah intervened.
"Let the record show that the witness remains silent to this question," he said.
When further pressed, the officer told defence counsel Sanjeev Teeluckdharry that he was questioning the accused about his movements.
But he repeatedly answered "I can't remember" to a series of other questions posed by the lawyer about his involvement with the accused in the days after the murder.
Mrs McAreavey's father-in-law Brendan McAreavey and her sister-in-law Claire McAreavey watched the exchanges from the public gallery.
Her widower John has returned to the island but cannot be in court until he gives evidence as a prosecution witness.
One of the main entrances to the Supreme Court building in Port Louis was blocked off ahead of the start of proceedings after part of a tree fell down in high winds last night.
A jury of nine - six men and three women - is hearing the case.
Almost 50 witnesses are listed to give evidence.
Though most Mauritians speak French Creole as their first language, court proceedings are being heard in English.
The case against Treebhoowoon, from Plaine des Roches, and Moneea, from Petit Raffray, was scheduled to last two weeks but is set to go on for much longer with judge Fecknah having warned that a "lengthy trial" was ahead.
It is already one the most high-profile criminal cases held on the island.
Mrs McAreavey, from Ballygawley, Co Tyrone, was the only daughter of Harte, the GAA boss who has steered his native county to three All Ireland championships.
The Legends Hotel, which has since been renamed the Lux Hotel, is in the fishing village of Grand Gaube, close to Mauritius's Grand Bay.
Mrs McAreavey taught religious education and the Irish language at St Patrick's Academy in Dungannon, Co Tyrone.
Her Requiem Mass was held close to her family home at St Malachy's chapel in Ballymacilroy - the same church in which she had married a fortnight before she was killed.
Then-Irish president Mary McAleese was among dignitaries at a funeral attended by more than 3,000 people.