Police have identified the Staten Island woman killed when a boat on a trailer detached and struck her as she rode her bike as 21-year-old Alexa Cioffi.

Investigators said Cioffi died at Staten Island University North Hospital after paramedics found her along Hylan Boulevard at around 4:30 p.m.

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A 22-year-old woman who was riding alongside Cioffi is expected to survive. 

Both women were struck by the boat, which police said was not properly secured to the 2015 Toyota SUV driving north on Hylan Boulevard.

Investigators said the car tried to overtake the two cyclists as they traveled in the right lane, crossing over into the center lane.

That's when police said the trailer detached from the car and collided with the women, pinning Cioffi underneath.

Authorities said the driver, who was not identified, remained at the scene. 

Police were not able to say whether or not the driver would face charges.