The child's body was found near the Globe Theatre
Detectives suspect the murder may be connected with a witchcraft ritual.
The Metropolitan Police's Serious Crimes Group have decided to give the unidentified dead child the name "Adam".
Pedestrians on Tower Bridge in London spotted the boy's torso in the River Thames in September.
Forensic experts estimate he was aged between five and six.
"Adam" is thought to be of Afro-Caribbean origin, according to detectives.
In October, detectives revealed the boy might have been the victim of a "ritual killing".
The investigation is now focusing on whether the boy was the victim of a ritual by witchdoctors, who it is believed use body parts to make medicines and potions.
During the investigation, officers consulted with Dutch police about an investigation into the death of a girl, whose body was left in a similar state.
No formal link, however, has been established between the two cases.
Police made national appeals for information about the discovery, which led to widespread publicity. However, they have still been unable to identify the boy.
Commander Andre Baker, of the Metropolitan Police Serious Crimes Group, said they were currently acting as the boy's "family".
"[This will continue] until we can identify him and his family.
Poster appeal
"We also want to remind everyone that he was a person, so that is why we have given him a name."
The investigating team had deliberated long and hard, and consulted the Metropolitan Police's independent advisory group about the name.
"It was considered that Adam is the most appropriate and acceptable name.
"As a step towards identifying his killers, it is important to establish his identity."
Earlier this week, a new appeal poster from the National Missing Persons Helpline was distributed to public places, including homeless hostels and hospitals.
Mr Baker said police would not rest until Adam's killer or killers were caught.