He was identified with the help of dental records, according to Västra Götaland police.
Police have not yet revealed the details of the forensic examination.
“We are not making any statements about the cause of death,” said Mats Glansberg, head of information at Västra Götaland police to TT.
The definitive post-mortem report is still not available and could take a few weeks.
“We are waiting for that report and at the same time a forensic examination of the body is ongoing,” said Glansberg.
The news that the body was that of Bobby – whose surname has not been revealed by Swedish media – confirms the police’s theory.
“We have thought all along that it was the boy. Now we know. When there is suspicion of murder it’s obviously important that you also find the body,” said Mats Glansberg.
The police’s interrogation of the boy’s mother and her partner, both of whom are being held in custody on suspicion of murder, is continuing. They deny the crime.
However, no other explanation of why the boy disappeared from a shopping centre in Gothenburg just after Christmas has been put forward.