While the sisters hail from Fairfax County, the New York City police are leading the investigation and said both women's ankles were bound with duct tape and they were duct-taped together around the waist, facing each other.
The National Center for Missing and Exploited Children posted on its website that Tala Farea had been missing since August 24 and she could be with her sister.
Tala and Rotana's mother also reported them missing a year ago.
The Farea family lived in Fairfax, Virginia, after they moved there from Saudi Arabia.
The younger sibling had been living with their mother, who is based in Virginia, before visiting her sister.
Police sketches of the two women found taped together in the Hudson River on October 24, 2018.
Anyone with information about the Farea sisters is urged to call the New York City Police Department's Crime Stoppers hotline at 1-800-577-TIPS.
They are insisting that the pair did not commit suicide and are waiting to find out the cause of death from the Chief Medical Examiner, which has not yet released findings from the autopsies. But the missing child report was withdrawn after it was claimed she was living with her elder sister in New York City.
Arab News reported that both sisters were in touch with their mother until about a week ago.
Their mother did lose contact with them about a week before the bodies were found.
A tweet from the General Consulate of Saudi Arabia in NY stated that the sisters were Saudi citizens and they are following this case closely with authorities. Tala was initially reported missing to the police but the search was called off after it was discovered she was with her sister.
The bodies had washed onto some rocks by the tide. They were fully clothed, wearing black jackets with fur trim and black leggings.