A suspect has been arrested in the fatal hit-and-run of Netflix star Sara Burack …  and authorities wasted little time in cracking the case.

Per the New York Post … Amanda Kempton was arrested and booked on suspicion of leaving the scene of a motor vehicle accident, a felony.

A family spokesperson told TMZ … they family was not aware an arrest had been made … and Southampton Town Police did not immediately respond to a request for more information.

As we reported earlier in the day, the star of Netflix’s “Million Dollar Beach House” was killed by a hit-and-run driver in the Hamptons on Thursday.

Our family source told us … Sara was struck around 2:30 AM Thursday along Montauk Highway, near Villa Paul Restaurant, in the Hamptons.

Sara suffered severe head injuries and several broken bones. And we’re told she was found quickly after the collision by someone in the area, who called paramedics … Sara went into cardiac arrest at the scene, but was revived. She was put on life support at the hospital … but there was no brain activity, and she was pulled off life support and died at 3 PM yesterday.