Who shot J. R. in the last episode of the 1979-80 season of “Dallas” (CBS, 1978-91)?

Kristin Shepard (Mary Crosby), J. R.’s sister-in-law, shot J. R in the last episode of the 1979-80 season of “Dallas” (CBS, 1978-91).

J. R. Ewing was played by Larry Hagman.