Skin tissue found under the fingernails of strangled honeymooner Michaela McAreavey could prove crucial to the police case against the three men charged in connection with her murder.
It is understood DNA tests on forensic evidence recovered from the body of the 27-year-old teacher are due to be completed by the end of the week.
The newlywed, who was the daughter of Mickey Harte, the celebrated manager of Ireland's all-conquering Tyrone gaelic football team, fought for her life against her attacker in her room in the luxury Legends Hotel in Mauritius, the island's police said.
Police chief Dhun Rampersad said: "From what we have obtained from her nails, the collections we have obtained from her nails, it looks like there may have been some struggle," .
On Monday her husband of only 10 days John McAreavey found his bride's body in the bath with the water running.
It is understood the Irish language teacher from near Ballygawley, Co Tyrone, interrupted burglars who had gained access to the room using an electronic key card.
Mr Rampersad said investigating officers would prefer Mr McAreavey, who was initially arrested but quickly ruled out as a suspect, to stay on the island for a few more days, until early next week, to help with the inquiry.
This may hamper the families' hopes of returning Michaela's body home by the weekend.
Three workers at the hotel were remanded in custody in connection with the brutal killing which has sent shockwaves through Ireland. Two faced murder charges and one conspiracy to murder.
The Mauritius Police Force said the two men charged with the murder were Avinash Treebhoowoon, 29, a room attendant from Plaine des Roches, and Sandip Moneea, 41, a floor supervisor from Petit Raffray.
Room attendant Raj Theekoy, 33, from Ramnarain Cottage faces the conspiracy charge.
The brief court hearing in Mapou on the north of the island heard claims that one of the defendants had been beaten by police officers during questioning - an allegation magistrate Bono Mally pledged to look into.
They were remanded in police custody for a week to return to court next Wednesday, when they are expected either to be formally charged or released.
Mr Rampersad said the evidence against the three suspects was circumstantial.
"They have not confessed but we have circumstantial sort of evidence but we are trying to find some other evidence to link them to the charge," he said.
It is understood the results of the DNA tests will be completed on Friday.
The commissioner said the use of the key card to open the couple's bedroom door was also critical to the case.
"Not all people have access to these cards," he said.
He said officers identified the suspects by checking who had access to the ground floor of the hotel and the rooms on that level.
It is hoped a trial will take place within six months.
Mrs McAreavey's brother, Mark Harte, as well as her husband's brother and parents have arrived in Mauritius to help with arrangements to take her body back for a planned funeral at St Malachy's Church, close to the family home outside Ballygawley, where she married on December 30.
Last night, the teacher's heartbroken father Mickey spoke of his devastation over the death of his "beautiful" daughter.
"This is the worst nightmare that anyone can imagine. If you think things can be bad, then you go beyond that because that is where we are," he said.
Mr Harte said his family had been left shattered.
Outside the house last night, he stood with two of his three sons, Matthew and Michael, and said: "This is too horrible to contemplate. We are just all devastated. It is the worst of the worst and our hearts are broken.
"We just loved our Michaela. She was such a good girl. Every father says that about their daughter, but I can say that without a shadow of doubt.
"She was a gem and we will always remember her.
"What a day she had on her wedding day. She was just radiant, a beautiful girl, and I just love her to bits. So does her whole family. We are so devastated.
"The McAreavey family are so special to us too. There is a special bond. John is a special lad. You have to be special if you're going to be Michaela's husband."
Legends Hotel is in the centre of the fishing village of Grand Gaube, not far from Grand Bay in the north-eastern corner of the island.
Mr McAreavey has spoken to a government minister in Mauritius and asked him to relay a simple message home: "I love my wife."
Books of condolences have been opened throughout Co Tyrone to give people an opportunity to pay their respects.