Kelly Armstrong’s family said she was last seen in August and they are determined to find her, RTV6's Myrt Price reported.

Relatives said they believe she is in danger because she left everything behind, including her children.

Armstrong’s sister, Shelly Rush, said she fears the worst has happened.

"I was calling her and not getting an answer. I was sending police over there to do welfare checks on her, with no response. After a while, things didn't seem right, so I reported her missing,” Rush said.

Family members said Armstrong’s boyfriend was the last person to see her and although he is currently in jail on an unrelated charge, he hasn’t been much help.

“He is currently in jail on an unrelated charge, and he's not being cooperative,” Rush said.

Volunteer Kris Morris was moved by the family’s efforts and has been helping with their search efforts.

"It broke my heart, and I've got three children and a 12-year-old daughter. I can’t imagine the feeling that (her children) go through every night trying to go to bed, wondering what happened and where she is," Morris said.

Volunteers said the search can be frustrating at times, but they said even though it’s disappointing, they're not about to give up.

"We’ve searched fields, woods, drainage ditches and waterways. We aren't leaving any stones uncovered. We're looking everywhere,” Rush said.

"We won’t stop until we find her. Whatever the outcome is, we will find her," Morris said.

Police said they’ve questioned Armstrong’s boyfriend, but he has not been named a suspect.