04/08/2015 05:00 EDT | Updated 06/07/2015 05:59 EDT

Roberta Ferguson: one of 65 missing and murdered women cases still unsolved in B.C.

On a warm August day in 1988, 19-year-old Roberta Ferguson walked away from a Cultus Lake campground — and vanished without a trace.

Almost 27 years later, her sister and legal guardian Verl Ferguson is still looking for closure — and blames the RCMP's handling of the case for the fact Roberta's body, and suspected killer, have never been found.

"I wish more would have been done," she said, wiping away tears. "I wish they would have really worked at trying to find her. Maybe she would still be alive."

The quiet teenager was camping with family and friends at the lake south of Chilliwack, B.C., when she decided to head home to Surrey. A member of the Dunvegan Cree First Nation, Roberta Ferguson was never seen again.

"She was a good kid. She didn't drink. She didn't [take] drugs" says her sister, now a cultural counsellor with the Fraser Region Aboriginal Friendship Centre Association in Surrey.

But when the family reported her missing, RCMP told the family to wait 24 hours.

"It seems like they weren't believing that she'd gone missing...At the time, I thought it was because she was native."

65 missing and murdered women in B.C.

A CBC News investigation has identified 230 examples of unsolved murders and missing women cases across Canada between the years of 1951 and 2015.

B.C. has the highest number of incidents, at 65.

- MORE STORIES | Missing and Murdered Indigenous Women and Girls

CBC News embarked on an exhaustive search for families of the victims. More than 110 families were interviewed nationally.

They were asked to rate the quality of the police investigation in each case, on a scale of 1 to 10, with 10 being excellent. The average rating was 2.8.

Verl Ferguson agrees with the failing grade.

"Right now, because it's been so long, it's all I can do is rate them at that low level."

Cases not taken seriously, says ex-Mountie

Private investigator and former Mountie Ray Michalko shares Ferguson's low rating of the police investigations into missing and murdered women.

He's made it his personal crusade to try to find out what happened to some of the 18 First Nations women still missing along northern B.C.'s infamous "Highway of Tears".

"It seems that resources are more readily supplied when the cases are involving, I guess I'm gonna say 'middle class taxpayers.'"

Michalko, who served with the RCMP for nine years, says cases involving indigenous women are often not taken seriously, despite a provincial inquiry into missing and murdered women that followed the conviction of serial killer Robert Pickton.

"The impression [families] get is that people they are talking to don't really care... It starts a vicious circle and makes it even more difficult for people to come forward."

Michalko is also critical of the RCMP's E-PANA taskforce, investigating the Highway of Tears cases.

The probe began in 2006 and has cost more than $25 million to date — with police only laying charges in one of the 18 cases.

"If those investigators worked in the private sector and spent $25 million with no resolve to anything, they'd be fired and never hired again," said Michalko.

Highway of Tears investigation funding slashed

Earlier this year, it was revealed the annual budget for the RCMP investigation has been cut by the province — from a peak of $5 million each year between 2009 and 2012, to $880,000 this year. The number of dedicated officers has also dropped from 70 to 12.

Nevertheless, contacted by CBC News, B.C.'s Justice Minister Suzanne Anton says she's confident the RCMP remains committed to solving the missing and murdered women cases.

"I am also confident that the flexibility remains…to move any investigation forward, and scale resources up and down accordingly."

Both Ray Michalko and Verl Ferguson fear the mystery of Roberta Ferguson's disappearance — like many of the 230 cases examined by CBC News — will never be solved, unless the killers themselves come forward.

"Somebody has to show up and say, 'Hey, here I am, this is my name. I killed so-and-so and I'm tired of living with myself.' Otherwise nothing is going to get done now," said Michalko.

Ferguson merely wants justice for her sister — and the other missing and murdered indigenous women across the country.

"Our children need to be taken care of, too. Not just everybody else's children."