Last year Beard confirmed detectives were working with forensic experts to create a DNA profile for the baby in a bid to find any family members on available databases.
In September the Herald reported that potential relatives had been identified.
“The baby girl’s DNA profile was obtained ... a group of people with a potential DNA familial link have been identified,” said Beard.
“Police have begun the process of speaking to some of these people in the hope of narrowing the group down and identifying the newborn’s mother.”
Beard said the work was “extremely complex” and would take some time.
“But we are determined to find some answers for the sake of this little girl,” he said earlier.
“As we’ve said right from the start, we want to make sure the baby’s mum gets the support she needs.”
The police investigation was described by Beard as “mammoth”.
It included reviewing the movements of more than 100 recycling trucks that had gone to the recycling facility the day the baby girl was found.
Police also released images of clothing and a blue bag found near the girl at the scene.
While they were unsure if the items were linked, they wanted anyone who recognised them to make contact.
Beard said it was not too late for the newborn’s mother or someone within her immediate circle of family or friends to come forward.
Anyone with information is urged to contact 105, quoting file number 210816/2825, or Crimestoppers anonymously on 0800 555 111.