Tala Farea, 16, and Rotana Farea, 23, were bound together with duct tape when their bodies were discovered back in October, about two months after they disappeared from a shelter in Fairfax, Virginia, authorities said.
"Today, my office determined that the death of the Farea sisters was the result of suicide, in which the young women bound themselves together before descending into the Hudson River," Chief Medical Examiner Dr. Barbara Sampson said in a statement.
The cause of death was drowning.
Authorities said they'd been living in Manhattan since Sept. 1, shopping, ordering lavish meals and staying at lofty hotels until a credit card they were using maxed out.
New York Police Department Chief of Detectives Dermot Shea said they may have been abused at home, according to ABC's New York station WABC.
People who knew the Farea sisters in Virginia told investigators that they made statements within the last year indicating "that they would rather inflict harm on themselves — commit suicide — than return to Saudi Arabia," WABC reported.
Shea said the NYPD has seen reports the sisters applied for asylum and reported they were physically abused. He said detectives were informed the sisters expressed a desire to "inflict harm on themselves, commit suicide" rather than return to Saudi Arabia after they had been in the United States about three years, according to the station.
A missing person's poster said the women were last seen on August 24 in Virginia, but their family hadn't seen them since November 30, 2017.