MAYS LANDING -- The family of a New Jersey teenager struck and killed by a New Jersey Transit train last summer is challenging the ruling that her death was a suicide.

Tracks on the Northeast Corridor (Mark Makela/Getty Images)

Tiffany Valiante's family filed a lawsuit this week to subpoena investigative files from NJ Transit, the Atlantic County Prosecutor's Office and the state's Southern Regional Medical Examiner's Office. The family's attorney, Paul D'Amato, says the agencies wouldn't provide the files without a subpoena.

The suit doesn't seek financial damages. D'Amato wants to review the documents to determine whether investigators missed clues or overlooked other possibilities in the 18-year-old Mays Landing girl's death.

Valiante was last seen at her cousin's high school graduation party the night she died last July. Relatives say she appeared happy, and D'Amato said toxicology tests showed no signs of alcohol or drugs.

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