It's been nearly four months since Eva Potts has seen her sister.

"I felt like I'm going crazy … everything reminds me of her."

When growing up on the Alexis First Nation in Alberta, Misty Potts was always a role model for her younger sister: an "amazing woman" who held a Masters in environmental studies.

"When she started something, she saw it through. She finished it," Eva said.

"She was very giving and kind and compassionate."

Today, Misty Potts is one of the hundreds of aboriginal women that are missing in Canada.

Misty's troubles began four years ago. She was living in Manitoba in 2011, working on her PhD., when her brother passed away. Shortly afterwards, Misty separated from her husband, who retained custody of the couple's young son.

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Eva Potts says her sister Misty was a dedicated mother and accomplished student. (CBC)

Eva said both events hit her sister hard. She began using marijuana regularly, before moving on to prescription medication and methamphetamine.

"She just kept getting deeper and deeper," Eva said. "She didn't want to try, she kind of felt defeated."

Eventually, Eva and her mother convinced Misty to return to Alberta and seek out help for substance abuse. Eva said she was hopeful for her sister's recovery, but things were difficult. A few days after returning to the Alexis First Nation, she suspected her sister was spending time with other drug users.

In late February, Misty left the family home. It would be the last time Eva would speak with her sister.

Police slow to react, family says

Police say Misty was last seen in March, seen getting out of a vehicle on the side of Highway 43. Eva says she doesn't see why her sister would do that.

Earlier this week, the RCMP said that aboriginal women go missing and are killed at a higher rate than the general population.

In the report, the agency said aboriginal women are most likely to be killed by someone they know and have pledged to make such cases a priority.

Eva Potts remains skeptical. While the RCMP constable now handling Misty's disappearance has been helpful, she's accused police of being slow to react when her sister first went missing.

She said they "didn't take it serious" when Misty first disappeared. She said they were slow to follow up leads suggested by the family. Eva said even when her sister was dealing with addiction, she kept close contact with her son back home. She's convinced Misty would not have disappeared willingly.

Police are now circulating photos of Misty. However, Eva wonders what may have happened if the disappearance got more attention early on.

"I wish they would have taken us serious instead of speculating on their own doing their own thing, and not listening to us."