Nine more children known to New Brunswick's child welfare system have died, CBC News has learned.

Seven of the deaths happened over the last 12 months, while two more children died in late 2016, according to new figures from the province's child death review committee.

The committee was created 20 years ago, after two-year-old Jackie Brewer was left to die inside a dark Saint John bedroom.

Since then, the committee has reviewed 145 deaths of children known to child welfare officials. At least 57 of those children died from unnatural causes, including abuse, neglect and homicide.

But how and why many died remains a government secret, nine months after CBC News revealed some of their stories in an investigation called The Lost Children.

"It's not transparent now, let's face it," child and youth advocate Norm Bossé said.

"I get the reports and I get to see all of them. But the public doesn't know anything."

In April, the government announced a review of its child death review system to try to make it more transparent.

Jackie Brewer died from neglect and dehydration in 1996. Her death sparked the creation of the child death review committee. She would be 23 now. (CBC)

No one from government was made available for an interview about that review.

But a spokesperson said an update on the review "and public transparency" will be announced before the new year.

Bossé said the government plans to re-do the committee's terms of reference and it will make more information available to the public, but he couldn't provide more specifics.

"Anything more than what the public has received is an advancement in transparency," he said.

Not all deaths reviewed

Child and youth advocate Norm Bossé says the current child death review committee system is not transparent. (CBC)

Of the seven children who died in 2017, four died from natural causes. Three deaths are still under investigation.

Without dates, names, locators or any sort of identifying data being released by the department, the circumstances of the two deaths from 2016 couldn't be determined.

Since 2014, the committee has reviewed 33 children's deaths.

All of those children were in care or recently received a service from the Department of Social Development.

At least 13 of those deaths were unnatural, including one homicide and three suicides.

The committee is supposed to review the deaths of all children in New Brunswick, according to its mandate.

But the committee has only been investigating cases of children who were known to child welfare officials, CBC News revealed earlier this year.

There continues to be confusion around what kind of deaths are being reported to the committee and investigated, Bossé said.

"If we're just reporting child deaths that are children who are in the minister's care or who received services, we're not tracking other children who might have died by accidents, for example, that might be preventable accidents."

Few details on 'serious' recommendations

Green Party Leader David Coon wants the government to tell the public more about how vulnerable children are dying. (CBC) While the Gallant government has promised to be more transparent about how at-risk children are dying, Green Party Leader David Coon said the public still knows little.

"Like a lot of things with this government, there is so much secrecy surrounding the machinations of government internally," Coon said.

The child death review committee released a report in June about a child's death, saying abused children shouldn't be sent back into a home with their abusers.

But neither the recommendations nor the government's response said anything about how that child died, whether he or she was abused, or how the child came to be returned to an abusive situation, if that's what happened.

These were all red flags for Coon.

"Some of the recommendations that were made by the child death review committee this June really suggest to me there's some pretty serious things going on in terms of the circumstances of the children's deaths that we're not hearing about," he said.

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Part 1: The Lost Children: The secret life of death by neglect

Jackie Brewer, the 2-year-old who was ignored to death

How New Brunswick's child death review system works

Part 2: The Lost Children: 'A child that dies shouldn't be anonymous'

Haunted by Juli-Anna: An 'agonizingly painful' preventable death

Part 3: The Lost Children: Change on horizon for First Nations child welfare

Mona Sock, a life stolen by abuse

Part 4: The Lost Children: Government weighs privacy over transparency in child deaths

Baby Russell: A few minutes of life, then a knife in the heart