Warminster Township police are trying to locate 21-year-old Ashley Keller, who was last seen around noon on July 4.
The National Crime Information Center lists Keller as "an endangered female."
Police say she may be in the Chicago area.
She is believed to be with 21-year-old Romulo Perez-Catalan, known as Rony. There are several active warrants for his arrest, according to police.
Perez-Catalan has been charged by Warminster police with burglary, trespass and criminal mischief for an incident on June 30.
Keller is identified as 5-feet-1-inch tall, weighing 130 pounds, with brown hair and blue eyes. She has a tattoo of a hummingbird with a flower on her right foot.
Warminster police are working with the Bucks County District Attorney's Office and the Federal Bureau of Investigation to locate Keller and Perez-Catalan.
Police report they are possibly operating an older blue, two-door vehicle with a dent on passenger door, rust around rear bumper on passenger side and back seat filled with items.
On Wednesday, the FBI obtained a Federal Flight from Prosecution warrant for Romulo Perez-Catalan. He is believed to be in the city of Chicago with Keller.
Anyone who has seen the couple is asked to call Detective David Bonacquisti of Warminster police at 215-443-2767.