(CNN) -- The mother of a missing 17-year-old honor student from North Carolina said she was stunned to learn that "20 different guys" passed through the home where the girl was staying and that the girl was allowed to drink alcohol while visiting family in Baltimore.
Phylicia Barnes of Charlotte, North Carolina, has been missing since December 28 after saying she was going out to get something to eat and maybe a haircut, according to Baltimore police. Maryland State Police and the FBI are also participating in the case.
Authorities have said they fear Barnes may have been harmed or abducted. Barnes left her debit card, and her mother said she has not answered her cell phone.
In an interview with HLN's "Nancy Grace" on Friday, Barnes' mother, Janice Sallis, said she spoke with Barnes' oldest half-sister multiple times before allowing Barnes to go to Baltimore.
"She knows how protective I was as her mother. She wasn't allowed to have a boyfriend," Sallis said. "She didn't have men; we didn't have men coming in and out of our environment."
Sallis said she was "stunned" and "devastated" after learning from one of Barnes' siblings that "there was a listing of 20 different guys going in and out" of where Barnes was staying and that her daughter -- who recently turned 17 -- was allowed to drink alcohol.
A Baltimore police spokesman has said more than 100 Baltimore police, Maryland State Police troopers and FBI agents have been working on the case.
Sallis said she had encouraged Barnes to reach out to her siblings on her father's side of the family.
"I encouraged her to go on Facebook to look for them because she hadn't heard from that side of her family, from her father, in over eight years," Sallis said. "And I, as a mother, didn't want my daughter not knowing who her other side of her DNA is. I didn't want her going from man to man looking for her father in relationships, so I encouraged her to look for her half-sisters online and maybe she could find her father that way because she hadn't heard from him in over eight years."
According to police, Barnes communicated through text messages with her half sister about 12:30 p.m. the day she disappeared. The ex-boyfriend of the half-sister was moving out of the apartment and said he saw Barnes on the couch at about 1:30 p.m., but when he came back to the apartment at about 5:10 p.m., Barnes was not there. The door was reportedly unlocked, and the music in the apartment was extremely loud.
Last week, Baltimore police spokesman Anthony J. Guglielmi said the FBI did a profile on the girl and found no reason she would run away. She is a good student with no emotional disturbances in her life, he said.
"The fact set of this case is different than anything else we've seen," he said.
Sallis made an emotional statement to CNN affiliate WBFF about her daughter.
"I want my daughter back," Sallis said. "She doesn't belong to whoever she's with. She doesn't belong with them. They are not her friends, they are not her family, they don't care anything about her. If they did, she wouldn't be where she's at."
Anyone with information on Barnes' disappearance can call 855-223-0033.
In Session's Jean Casarez and HLN's Natisha Lance contributed to this report.