A B.C. Supreme Court judge reviewing evidence from a custody dispute determined that the father of four children sexually and physically abused three of them, contrary to the findings of a flawed Vancouver Police Department investigation.

The mother of the children, who was awarded sole guardianship and custody in the 2012 court judgment, is now suing the province, saying it was negligent and acted in bad faith in allowing her former partner unsupervised access to the children during the dispute.

The mother's lawsuit against the province is currently on trial at B.C. Supreme Court in Vancouver and has already gone on for more than 80 days.

In addition, the mother is asking the Vancouver Police Department to reopen its investigation into allegations her former partner sexually abused their three children. The department closed its investigation in 2010.

"I want what is proper law. It's nothing vindictive, or anything like that," said the woman, whose identity cannot be revealed in order to protect her children.

"My ex is — he obviously is a very dangerous person. Like he didn't stop. I would like to see him properly prosecuted... That's all, because there's no sign that he's gonna stop unless something like that happens."

She says her world was flipped upside down two months after she and her husband separated in the fall of 2009 when, acting on only slight suspicion, she asked her three eldest children whether their father ever did anything to them.

She said she was expecting her children to respond with blank looks and confusion, but instead they began blurting out disturbing allegations that shocked her.

"The only thing I can think of now is Jekyll and Hyde, because… I just actually never could have fathomed what he was doing," she told CBC News in an exclusive interview.

A 'Kafkaesque' nightmare

She called the Ministry of Children and Family Development's helpline the next day, and called the Vancouver Police Department several times to seek assistance.

An order of the court was issued in October of that year, restraining the father from any contact with the mother or the children.

However, in December 2009, Justice Paul Walker — the same judge who ruled in the couple's later custody dispute — varied this order to allow the father supervised access to the children for specific hours.

Throughout this period, the father, along with his family and friends, made calls to Ministry workers and eventually the police, registering concerns about the mother's mental capacity.

In his custody dispute judgment three years later, B.C. Supreme Court Justice Paul Walker deemed the behaviour "a baseless attempt to discredit her."

However, at the time, the authorities decided the frantic mother was unreliable, and also likely in need of a mental assessment.

The Ministry took the kids away from their apparently unstable mom, and placed them in foster care, with an aunt and uncle, in December 2009.

After a series of interviews with the parents and children that December and January 2010, the senior investigating VPD officer, along with officers from the RCMP Behavioural Sciences unit, determined that the allegations against the father were unfounded, and closed the investigation.

Later that year, a social worker began allowing the father unsupervised access, contrary to the original 2009 court order, which their mom says allowed the abuse to continue.

The more she protested, the more she was labelled as being crazy. - Jack Hittrich, lawyer for the mother

"It was, it was like, one professional described it: 'Kafkaesque' is the best term that comes to mind. It's as if the people involved were just twisting everything," the mother said.

Jack Hittrich, the mother's lawyer, says the Ministry of Children and Family Development was negligent, reckless, and acted in bad faith.

"When mom was frantically trying to convince the ministry that the sexual abuse allegations were real, they basically labelled her as crazy. And the more she protested, the more she was labelled as being crazy," he said. "It's a horrific nightmare."

Hittrich doesn't think the mother could have accomplished more by protesting more, and that institutional failures must be corrected.

"Until the child sex abuse lens is refined and there's more sensitive processes in place, children are at risk," he said.

VPD officer 'smitten' with father

A former RCMP superintendent who reviewed the police interrogation videos, testified in court that the VPD investigation was deeply flawed.

"I think the police formed the opinion that the mother had no credibility, therefore they didn't react and follow the investigation the way it should have been followed," said Glenn Woods, who worked for the RCMP for 35 years.

Woods, who spent 11 career years as a criminal profiler, said after watching the footage, he believes the senior officer involved in the case developed negative attitudes early on about the mother — and positive feelings about the dad.

"I used the word 'smitten.' I just got a sense that the interaction between the officer and the father was almost at times kind of a social interaction, as opposed to a police interview or interrogation."

Woods told the CBC that Vancouver Police should have fresh eyes look at the file, saying "I think an effort has to be made to take another look at this case."

In his judgment on the custody dispute last year, B.C. Supreme Court Justice Paul Walker agreed with Woods' critique of the police interrogation, writing "I was struck by how quickly and easily [the father] took control of the interview. It appeared to me that the officer was enamoured of (the father) in some way."

In his conclusion after reviewing footage of what he characterized as several flawed interviews, Walker wrote "I have determined that I can place no weight on the conclusions reached by the VPD… that there was no merit in the sexual abuse allegations."

Walker also determined, from the evidence presented, that the father sexually abused three of his children, exposed them to inappropriate sexualized knowledge, and physically assaulted them and their mother.

He gave full custody to the exonerated mother, and said a restraining order would be required against the father.

Father maintains innocence

CBC News spoke with the father, who maintains that his ex-wife fabricated the sex abuse claims in order to gain sole custody of their children.

"By itself, that allegation is nuclear. You light off that allegation and there's radioactivity forever. It never, ever goes away," he said.

The senior Vancouver Police officer who cleared the father refused comment, referring CBC News to the department.

Sgt. Randy Fincham, media relations officer for the department, wrote to the CBC in an email, "The judge is more than entitled to have an opinion about the quality of the police investigation" and "in the event that new evidence is brought forward in any investigation, the police retain the ability to reopen, continue or advance their investigation."

Beyond that, he stated the department "is not at liberty to discuss an ongoing court process, as it may impact the final outcome of the proceedings."

Mr. Justice Walker's decision was rendered last year. The Vancouver police are not party to the current negligence lawsuit against the province.

Sgt. Fincham did not answer questions about whether the case merits a review, or what should be done about the father in the community, given the judge's finding that he sexually abused his three children.

The Minister of Children and Family Services, Stephanie Cadieux, wrote in an email it would be inappropriate for her to comment on the case, as it is before the courts, stating "the safety and well-being of children is always the Ministry's first priority."

Read the Supreme Court judgment online (CAUTION some of the content is disturbing)