Police released a sketch and surveillance footage of a woman running from the subway station. Menendez was arrested after a passer-by saw her on the street and thought she looked like the wanted suspect. Witnesses identified her in a lineup and she was questioned by police, when she implicated herself, according to police and prosecutors.
Angel Luis Santiago, who used to work at the Queens building where Menendez's mother and stepfather live, said he was shocked by her arrest.
"It surprised me what she did," he said. "She never acted that way."
Menendez's next court appearance is scheduled for Jan. 14.
Sen was the second man to die after being pushed in front of a New York City subway train this month. Ki-Suck Han was killed in a midtown Manhattan subway station on Dec. 3. A homeless man was arrested and charged with murder in that case and is awaiting trial. He claimed he acted in self-defense.
Such subway deaths are rare, but transit officials said last week they would consider installing barriers with sliding doors on some subway platforms. Other cities including Paris and London have installed such barriers.
Associated Press Writer Karen Matthews contributed to this report.