DNA tests have been used to help rule out 30 men suspected of being missing Ben Needham from Sheffield.
Since April last year, when South Yorkshire Police set up a specialist team to investigate the disappearance of Ben, who vanished 25 years ago this weekend, officers have eliminated 30 people.
The team said there are a small number of others who still need to be eliminated.
A South Yorkshire Police spokeswoman said: "Since launched our investigation in April 2015 to support Greek authorities in the on-going search to find Ben, we have carried out extensive enquiries and explored a wide range of enquiries.
"We have eliminated over 30 people who were suspected to have been Ben using DNA and other means.
"Enquiries continue regarding a small number of other people who still need to be eliminated.
"Nearly 3,000 people have been spoken to during the course of the investigation and hundreds of people have come forward with information to help our inquiry.
"The investigation is on-going and we remain committed to finding answers for Ben’s family about what happened to him 25 years ago."
Ben was 21 months old when he vanished from outside a farmhouse his grandfather Eddie was renovating in a village on the Greek island of Kos on July 24, 1991.