Ray and Gwen Lins never imagined they'd spend a Thanksgiving without their 24-year-old daughter, Michelle Lee Rust.

Since July, when she mysteriously disappeared on her son's third birthday, the Lins have kept hoping that she would show up on their doorstep in Arbutus. It's too much for them to imagine any other outcome.

"We'll never stop looking for her," Rust's father, Ray Lins, said yesterday as the couple appealed for the public's help in finding their daughter.

From the beginning, Baltimore County detectives termed Rust's disappearance suspicious. But now, police say they believe she was a victim of foul play.

"There's no logical explanation for her disappearance," said Bill Toohey, a county police spokesman. "By all accounts, she was devoted to her son and would never have left him or her family."

Rust was supposed to go to Wal-Mart to buy supplies for her son's birthday party, to be held at her house on Clarke Boulevard the afternoon of July 20. But, police said, no one saw Rust leave her house or drive away in her green Dodge Caravan.

The van was found later that day on Clyde Avenue in Lansdowne.

"One of our hopes is that someone saw the car," Toohey said.

Rust's bank and credit card accounts have not been touched, confirming her family's hunch that she did not leave on her own.

Initially, family, neighbors and friends plastered telephone poles and storefronts in the area with missing posters. Then they formed search teams in hopes of finding Rust, who is diabetic. As time went on, a $10,000 reward was offered, which still stands. Yesterday, her parents talked with reporters again about their only daughter, hoping the news media attention would spark someone's memory.

They talked about how she loved children, especially her son.

"She was upbeat about everything," her father said. "She was willing to help anyone with anything."

A lifelong resident of Arbutus, Rust graduated from Lansdowne High School. She sang in the choir and helped with children's programs at Halethorpe Community Church. Rust also had worked at a day care center before she became a stay-at-home mother.

"Her son is only 3. He doesn't understand all this," Ray Lins said. "We just tell him the truth: 'Mommy's missing, and everyone is looking for her.' "

So far, detectives have been able to rule out only Rust's parents as suspects, based on their alibis on the day of their daughter's disappearance.

Police are talking with other relatives and neighbors, including Rust's husband of five years, but have not named anyone as a suspect in the case.

"Sometimes, you see stuff, and it doesn't mean anything at the time," her father said. "We ask anyone out there who thinks they might know anything about what happened to her -- no matter how small -- to come forward."

Rust is described as white, 5 feet 4 inches tall and 140 pounds with red hair and blue eyes.

Anyone with information on the case is asked to call police at 410-307-2020, or Metro Crime Stoppers, which is offering a reward of up to $10,000 for information that leads to an arrest and indictment, at 410-276-8888.