The 28-year-old New York man was visiting a woman on the Kearney Avenue side of the Chateau Apartments on Gorge Road Wednesday night when her boyfriend showed up, neighbors said.
The couple was celebrating the woman's 36th birthday, they said.
After hearing them inside, the boyfriend left and returned with a friend, they said.
A loud bang startled the neighbors, who discovered the 6-foot-7-inch victim had awkwardly landed backwards on a car parked two stories below.
He was bleeding from the back of the head -- the victim of severe head trauma -- when an ambulance took him to Hackensack University Medical Center, they said.
"The hood of the car was smashed. It was crazy," one said. "He was really agitated when they were trying to revive him."
The man remained intubated in intensive care at HUMC with what were believed to be severe and permanent injuries.
Bergen County prosecutor's investigators questioned the boyfriend. The second man fled before police arrived, neighbors said.
There apparently were no signs of a struggle in the apartment.
The Bergen County Prosecutor's Office was investigating with borough police. The Bergen County Sheriff's Bureau of Criminal Identification collected evidence.
Anyone with information that could help the investigation is asked to call the prosecutor's office at (201) 646-2300 or Cliffside Park PD: (201) 945-3600.
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