Ben Needham's mother Kerry broke down in tears when British detectives showed her a "significant" item they had discovered during their search for the toddler on the Greek island of Kos.
Revealing details of the dramatic moment, Detective Inspector John Cousins said he now believed the toddler died in an accident.
The item, which he has not identified, was believed to be in the toddler's possession on the day he went missing on the Greek island 25 years ago.
DI Cousins said today: "I met with Kerry and other members of her family over the weekend. They were shown the item that was recovered. It was an item that Ben was in possession of at the time he disappeared. Kerry was able to confirm this. It was an emotional time for all of us."
The revelation comes as Ben's mother said she hoped a Greek digger driver "is burning in hell" after taking secrets about the youngster's death to his grave.
Police launched a fresh search on the island amid claims Konstantinos Barkas, also known as Dino, may have been responsible for Ben's death as he was clearing land with an excavator near the spot where the child had been playing on the day he vanished.
Barkas is believed to have died from stomach cancer last year and South Yorkshire Police has now formally ended its latest search.
In a press conference yesterday, DI Cousins said 93 items, mostly of "low interest" had been discovered during recent searches on Kos - some of which were due to be taken back to the UK for examination.
But one item found on October 15 was said to be of "greater significance" and was believed to have been in Ben's possession on the day he went missing on July 24 1991.
However, DI Cousins refused to reveal what exactly had been discovered.
Speaking at the scene, Detective Inspector Jon Cousins said: "My team and I know that machinery, including a large digger, was used to clear an area of land on 24 July 1991, behind the farmhouse that was being renovated by the Needhams. It is my professional belief that Ben Needham died as a result of an accident near to the farmhouse in Iraklis where he was last seen playing.
"The events leading up to and following that incident have been explored by my team of experts to great lengths. The fact that we have not had a direct result during this visit to Kos does not preclude the facts that we know to be true.
"An item found on Saturday, which I have shown personally to some of Ben's family, was found in one of the targeted areas at the second site, very close to a dated item from 1991.
"It is our initial understanding that this item was in Ben's possession around the time he went missing."
Ben's mother Kerry had earlier said that Barkas had "taken a secret to his grave" and now hoped the digger driver was "burning in hell" for failing to come forward while he was still alive.
Kerry also said she wants to "tear up" the whole island as the police search came to a close.
After the police announcement today, she thanked South Yorkshire Police for their "determination" to find answers.
She said: "There are no words to describe how grateful we are to South Yorkshire Police and the Hellenic Search and Rescue team and Red Cross / Red Crescent volunteers - but I will try.
"For 25 years we have felt alone and adrift as we searched for answers. This is the first time anybody has properly listened to us and cared enough to try and help.
"On behalf of my family I also want to sincerely thank Superintendent Matt Fenwick, Detective Inspector Jon Cousins, Ian Harding and Ian Marshall for their kindness compassion and sheer dedication. Not to forget all the other officers who have worked tirelessly to help our family."
"We also want to thank the British media for showing us so much compassion and allowing the police to get on with their job.
"It was never going to be a happy ending and we will have to decide at a later date where we go from here."
Ben Needham's father Simon Ward added: "I would just like to reiterate my thanks to the police officers and to all the volunteers who have been working on Kos."
Cousins said the recovery of the item added to his belief that material had been removed from the farmhouse on or shortly after the 21-month-old disappeared.
Despite this stage of the investigation coming to an end, the officer pledged to continue searching for answers, and paid tribute to Ben's family.
He concluded: "We remain committed to the investigation and it will not simply close; myself and Detective Superintendent Matt Fenwick will retain ownership of it and if new information comes to light, we will investigate it thoroughly.
"We will not stop in our quest to find further answers for Ben's family."
British investigators are still searching for the JCB digger that they believe ran over and killed Ben.
Ben, from Sheffield, disappeared on July 24, 1991, aged 21 months, after travelling to Kos with his mother and grandparents.
The latest search operation was prompted by information that digger driver Konstantinos Barkas, also known as Dino, may have been responsible for the toddler's death, as he was clearing land with an excavator near where Ben was playing on the day he vanished.
Timeline of events charting the disappearance of Ben Needham on the Greek island of Kos 25 years ago
Ben Needham vanishes while playing near the grounds of a farmhouse in the Iraklis region of Kos, which his family are renovating. His mother, Kerry Needham, and grandparents raise the alarm with local police and conduct a full search of the area.
• July 26 1991: Eyewitness reports claim a boy matching Ben's description was found at the local airport on the day he disappeared. That boy has never been traced.
• September 1991: The Needham family return to England due to illness, but vow to continue the search.
• June 2003: The Metropolitan Police issue an image of what Ben might look like at age 12-14 years old.
• 2004: An anonymous businessman offers a reward of £500,000 ($854,000) for information leading to Ben's safe return.
• October 2010: Another public appeal is made by Ben's mother in the run-up to what would be his 21st birthday.
• May 2011: The BBC airs a programme called Missing 2011, which includes a piece on Ben's story and the campaign to find him.
• September 2011: Greek police on Kos officially re-open the case and grant the family a face-to-face meeting with the island's prosecutor.
• October 2012: South Yorkshire Police in Kos begin digging up mounds around the property where Ben went missing to look for his remains.
• December 2013: Ben's mother accuses then-prime minister David Cameron of not giving her case the same backing as he gave the parents of Madeline McCann. It comes as a dossier is produced containing reports from eight witnesses, none of who know each other, who all saw a boy possibly matching Ben's description with the same Greek family.
• December 2014: Lawyers representing Ben's family say they may take legal action to try to force the Government to make a decision about funding a new police investigation.
• January 2015: The Home Office agrees to fund a team of British detectives to help search for the toddler.
• March/April 2015: Three generations of Ben Needham's family travel to Greece to follow up a "strong" lead that a man living there believes he may be the missing Brit due to having no photographs of himself under the age of two and no knowledge of where he was born. The man is later ruled out.
• May 2015: Ben's family make a fresh appeal on Greek television for information regarding the disappearance.
• September 2016: Ben's family are told to "prepare for the worst" by detectives leading the investigation, amid the belief the 21-month-old was crushed to death by a digger - the driver of which died in 2015. It comes as police arrive in Kos to begin excavation work in the belief the boy's remains may be buried near the farmhouse
• October 16 2016: Officers formally end a three-week search of two sites on Kos. Detectives said they had accumulated more than 60 items of interest that would be brought back to the UK for forensic testing.
• October 17 2016: South Yorkshire Police announces that it believes Ben died as a result of an accident near to the farmhouse where he disappeared.