Anna Maciejewska, 44, disappeared in April 2017 and hasn't been heard from since.
On Saturday, Maciejewska's friends hosted a vigil near the Chester Valley Trail parking lot on the anniversary of her disappearance.
Her car was found in the lot about a month after she vanished.
SEE ALSO: 6abc True Crime: What was bothering this mom before she vanished?
The case is being investigated as a homicide. A $30,000 reward is being offered for information leading to her whereabouts.
During an edition of 6abc True Crime in 2019, Action News reporter Annie McCormick sat down with Maciejewska's friends, who have their own theories. She also caught up with former 6abc colleague John Rawlins, who extensively covered the case.
You can watch the full True Crime episode below: