No one has yet been arrested.
Yesterday, sources confirmed JJ's mother was pregnant but were unsure when the baby was due. Police and Child, Youth and Family refused to comment.
Last week, CYF said it had been looking for JJ and his mother after a person concerned about his wellbeing contacted the agency.
That contact was made four weeks before he was killed. CYF staff visited his Takitimu St home several times but could not find him or his mother.
While the agency refused to comment specifically on JJ's mother and its current involvement with her, northern region manager Grant Bennett outlined what could happen in such a case where a mother had another baby.
"As soon as Child, Youth and Family is aware a child's safety may be at risk, we take steps to assess the situation. That includes concerns for an unborn child. If the concerns are of a sufficiently serious nature, then children will be removed. Ultimately our priority is that child's welfare."
Police are still investigating the death of another toddler, 6-month-old Serenity Jay Scott, in a Waikato house in April. No one has been arrested. Serenity Jay's mother, Chelsea Scott, is pregnant with her third child.
Police investigating JJ's death have vowed to get to the bottom of what happened.
Detective Inspector Scott Beard said that as in most child abuse cases, the investigation would be slow.
Police had spoken with JJ's mother and her boyfriend. Another couple also lived at the house and had been interviewed. Their two infants, who were at the house when JJ died, have since been taken into CYF custody.
Mr Beard said last week that the explanations the four adults had given about JJ's injuries were inconsistent with the findings of the autopsy and urged them to tell police everything they knew.
He said the investigation team were also interviewing friends and associates of those who lived at the house.
"There hasn't been a lot of change at this stage. But we're into the groundwork now," he said. "There is no progress on exactly what happened to JJ. It's slow progress - that's homicide inquiries - but we'll keep going."
The Herald has learned JJ's father, James Robert Ruhe, was sentenced to four-and-a-half years' jail last year on burglary charges.
A Department of Corrections spokesman said Ruhe was "pretty devastated" about JJ's death. He did not seek compassionate leave to attend the tangi in Kaeo last Thursday.
Ruhe's supervisor spoke with him and his family and a "collective decision" was made that he not attend the service.
But Ruhe has been moved to a prison closer to his family, and will remain there for about a month.
"It is a compromise that means his family can go and visit him and he can spend time with them," the spokesman said. "They can grieve together."
A memorial service for JJ would be held at Ruhe's temporary facility, and his family would be invited.
Corrections was also offering Ruhe counselling and had ongoing contact with his family to ensure he had the right support.
CONTACT
If you know what happened to JJ, contact police immediately on (09) 524-1925 or Crimestoppers anonymously on 0800-555-111.
CYF pounced to protect newborn
In a similar case in Christchurch, a newborn was taken from a mother whose 7-month-old had previously died violently.
Staranise Orangaiti Hinerangi Waru died in February 2006 after suffering severe injuries as a result of being violently shaken.
A year later, police told Child, Youth and Family that Staranise's mother, Nyree Hopa, was pregnant, and expressed concerns for that baby's safety. When the infant was born, it was put in the care of the parents of Miss Hopa's partner, Robert Waru.
No arrest was ever made over Staranise's death. Both Miss Hopa and Mr Waru repeatedly refused to speak with the police, and continued to maintain their silence at a coroner's inquest on the basis that they could incriminate themselves.
