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UPPER DARBY, Pa. (CBS) — The family of Amanda De Guio is pleading for help after she vanished nearly four years ago.

Authorities in Delaware County say the then 25-year-old woman disappeared from her Drexel Hill home on June 7, 2014.

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Police believe De Guio may have been the victim of foul play.

Since her disappearance, there has been no contact and no activity on her credit cards.

On Monday, in a press conference held alongside the Upper Darby Police Department, the family continued to beg for closure.

Authorities confirm that two detectives will begin to work around the clock on the case, but no longer investigating it as a missing person case but rather a foul play case.

Family members concede that she has a drug problem and engaged in prostitution, but say she kept up on her bills and doted on her two daughters.

De Guio’s family pleaded with the public to provide assistance and to offer any information.

Her mother, Joanne De Guio, issued a tearful plea.

“To the person that knows, please have a heart. If not for us, for her children. They need an answer. They’re older now, they miss their mom and they need a mom,” she said.

Search efforts have been endless as the family, private investigators, and the general public continually searched for Amanda in the Philadelphia area, notably in Kensington.

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During a March 2015 press conference, Upper Darby Police Superintendent Michael Chitwood said that the case was eerily similar to the 1977 murder of Holly Maddux in Philadelphia, but he was also looking into the possibility that De Guio may have been the victim of human traffickers.

Maddux was killed by her former roommate, Ira Einhorn. Her mummified body was later found stuffed in a trunk in a closet in his West Philadelphia apartment.

Together, Amanda’s mother, father, and Police Superintendent Chitwood asked anyone with information on the missing mother of two young daughters to please come forward.

“We honestly believe that somebody out there knows Amanda’s whereabouts today,” said Kevin Ryan, a private investigator working with the Upper Darby Police Department.

“Every missing deserves a voice, and we are that voice,” added Ryan.

De Guio is described as about 5-foot-3 and 120 pounds, with brown hair and blue eyes. She has several tattoos, including a map of Italy and the name “Tommy” on her right torso, and the initials “SC” on her left ring finger. She was known to go by several other names including Gianna, Adrianna, and Stacy.

A reward of $5,000 is offered by the Police Foundation for any information that could lead to finding De Guio.

Anyone with information is asked to contact Upper Darby Police Department at passcrimetips@udpd.org or 610-734-7693.