After just a day of deliberations, a Brooklyn jury convicted a man for hunting down and killing his ex-girlfriend as she headed to her correction-officer job on Rikers Island.

Keon Richmond, 37, was convicted of killing correction Officer Alastasia Bryan, 25, on Dec. 4, 2016, while she was sitting in her vehicle near the intersection of Avenue L and East 73rd Street in the Bergen Beach section of Brooklyn.

In the three days leading up to the shooting, Richmond had been tracking Bryan’s movements with a GPS device that he attached to her car.

He was apparently enraged over losing a white BMW that Bryan leased for him in her name while they were dating between 2014 and 2015.

Bryan allowed him to continue using the car after they split but then alerted the NYPD in August 2016 when Richmond began falling behind on the payments.

Richmond’s lawyer, Gregory Watts, did not respond to a request for comment from The Post on Monday.

The convicted man faces up to 40 years in prison when he is sentenced Dec. 4.