33-year-old Melanie Liverpool-Turner admitted to pushing Connie Watton, 49, off of the Times Square subway platform in 2016.

The crime incited a fear felt by many New Yorkers, and in doing so, propelled the story to the forefront of public awareness.

According to her attorney, Aaron Wallenstein, Liverpool-Turner had just been released from a psychiatric facility 5 days before she killed Watton. Before being admitted to the facility, she had falsely claimed to have pushed another person onto the subway tracks.

Police determined that individual had actually committed suicide, but prosecutors asserted that witnessing the suicide influenced her to kill Watton. Assistant District Attorney David Drucker argued in a court filing that it had "helped put in her mind the ideas and thoughts that led to" Watton's killing.

Prosecutors claimed that Liverpool-Turner's false statement indicated that she had:

"a motive or reason to commit this otherwise senseless and purposeless crime."

You can view CBS New York's coverage of the trial below:

Woman Who Pushed Stranger To Her Death On Subway Tracks Gets 20 Years To Life www.youtube.com

The attack against Watton was witnessed by other commuters, and one followed Liverpool-Turner to point her out to the police who responded. When police confronted her, prosecutors said that she told them that she had pushed someone onto the tracks.

Liverpool-Turner pleaded guilty to second degree murder last month and was sentenced on Friday to 20 years to life in prison.

Wallenstein commented on her taking responsibility for the killing:

"A woman lost her life and Ms. Liverpool took responsibility. She led an exemplary life until she had these illnesses and issues."

He further told The Associated Press that the case is a "tragedy, no matter how you look at it" and that Liverpool is remorseful, but intends to appeal the sentence.

After assigning the longest possible sentence for second degree murder, Justice Michael Obus characterized Watton's death:

"Thousands of people ride the subway every day. This is truly the quintessential urban nightmare - when a total stranger takes it upon themself to snuff out someone else's life."

The murder and the sentence raises questions about mental illness and the justice system. And unfortunately there are no easy answers.