Ala. Mom of Infant Vanished 3 Weeks Ago - Boyfriend Says She Went to Store, Never Returned

The search continues for a 30-year-old mother who hasn't been seen since February 17 - three months after the birth of her third child.

The boyfriend of Tiffany Smitherman Osborne told investigators she stepped out to get a pack of cigarettes, and never returned.

Police in Midfield, Alabama, confirm Osborne was reported missing two days after she left her boyfriend's home to go to the store.

Investigators said the store was only a block away from the home, and closed at the time.

The boyfriend told police he and the couple's 3-month-old baby boy fell asleep, and when he awoke, she was nowhere to be found.

Osborne apparently left the boyfriend's house without her phone.

The missing woman's mother spoke to NBC News, and said she's worried something bad happened to her.

"What I don't understand is why she would walk to the store so late at night, especially when they have more than one vehicle sitting in the yard," said Cathy Smitherman, Tiffany's mom.

"She would never just walk out on her children," Smitherman added. "And she would never not let anyone know where she's going. That's just not her."

Osborne's friends have joined the effort to find her, spending last weekend knocking on doors and handing out flyers with the missing woman's image.

Osborn was living with her mother at the time of her disappearance.

Smitherman is now caring for the infant as well as Obsorne's other children - two daughters, who are 12 and 7.