"The police investigation is continuing to establish the full circumstances surrounding her death," he said.
"Enquiries at the Weymouth address are continuing and the occupants are currently co-operating with police."
Adkin said the investigation into the suspicious death was still in its early stages.
On Monday police said the family was self-isolating and officers wore full PPE at the address. The Ministry of Health refused to confirm further details.
The toddler's death has rattled neighbours, who said they used to wave to the girl as she passed their house and saw her playing on a small plastic slide in the property's front yard.
One Gibbons Rd resident told the Herald she had left flowers for the family and hoped the community could come together to mourn. She said she also had a young daughter and the death had shaken her.
She said detectives had questioned her about whether she had seen or heard anything unusual.