A note scrawled by a prison guard minutes before her death was the clue that led to her killer, Orange County prosecutors said at the trial of her husband, who is charged with arranging the killing.

Elizabeth Begaren scribbled down the license plate number of a car that followed her onto an Anaheim freeway on-ramp in 1998, jurors were told Wednesday during opening statements in Superior Court.

Her husband, Nuzzio Begaren, was driving the family sport utility vehicle. He pulled over and a gang member got out of the other car and shot her, prosecutors contended.

Police found a torn-up piece of paper in the dirt by the side of the freeway and reassembled it. On it, Elizabeth Begaren had scribbled the words “light blue” and the plate number, prosecutor Larry Yellin said.

That led investigators to a Buick Regal driven by gang member Guillermo Espinoza, authorities said.