It has been more than a year since Sheila St. Clair was last seen.

Authorities said the 48-year-old Duluth woman was planning to travel to the White Earth Reservation in western Minnesota last summer, but she never arrived and family members haven't heard from her since.

Police have offered a reward and indicated that foul play could be involved, but her disappearance is still very much a mystery, said Lt. Dan Chicos of the Duluth Police Department.

"I wish I had some big revelation that we were able to account for her whereabouts at this point, but I don't," Chicos told the News Tribune recently. "We're still actively following up any leads as we get them. There isn't a week or a month that goes by where we don't think about her and what happened."

Police described St. Clair's disappearance as "extremely suspect," noting that it is unusual for her to drop out of contact with family. In October, they announced a $1,000 reward available to anyone who provides a tip that leads to the "arrest and conviction of the person or persons responsible" for her disappearance.

Chicos, commander of the Major Crimes Bureau, said the case has been challenging and frustrating for investigators. It is highly unusual for missing persons cases to reach the one-year mark, he said.

"The question is: The further removed we are from that day, do we forget about it?" Chicos said. "The answer is absolutely not. When you talk to a family member, you feel the pain and trauma that they're suffering and you want to provide them answers. Where is she? What happened? That remains our focus."

Duluth resident Shawn Carr said he had met St. Clair a few times, but didn't know her well. He's now helping organize efforts to bring her home.

"She was a very nice lady from what I knew of her," he said. "She's deeply missed by a lot of people. There's definitely a big void there."

Carr, a member of the activist group Idle No More, said the situation is all too familiar - citing trends in the disappearances, trafficking and murders of Native American women.

"The overall sense is we need to safeguard our Native American communities and women and families," he said. "For whatever reason, it seems that Native American women tend to be victimized more, or it's a more painful issue for us."

Chicos said the case has been particularly difficult because police did not receive the missing person report for several weeks. He said St. Clair's last confirmed sighting was on Aug. 15, 2015, but she was not reported missing until Sept. 10.

Chicos said investigators have worked to piece together St. Clair's life - her daily patterns, the people she associates with, the places of interest for her - in hopes of finding the clues that might help solve the case.

"The message we want to send is that if you know anything, no matter how small you think it might be, to please contact us," he said. "Any information can be helpful. It might seem insignificant, but it could be one more piece that helps us put the puzzle together."

Carr also is asking for the public's help. He said he and other activists hope to put together a ceremony in the coming weeks to highlight the case.

Several family members attended a similar event last October, when police announced the reward.

"We need my auntie back," an emotional Dustin St. Clair told community members at that event. "We're lost without her. The community is lost without her. We need her back."

Attempts to reach family members in recent weeks were unsuccessful. However, Chicos said police have attempted to remain in close contact and provide regular updates for St. Clair's family.

"Somebody knows something," Chicos said, "and these are the people we need desperately to come forward to give us that information so we can provide that closure and those answers to her family."