Tonight on PBS’ "Finding your Roots with Henry Louis Gates Jr.," actress Khandi Alexander learns that her grandfather may’ve been killed by white coworkers in Jacksonville, Florida, in 1935. Neither her mother nor grandmother ever talked about her grandfather’s, Joshua Masters,’ death at age 25 while working at a rosin factory. "Maybe it was too painful," Alexander says, at first in a questioning voice. Then she’s sure: "Maybe it was too painful."

Masters had worked as a factory distiller. It was a job normally reserved for white men whom Gates, after some investigation says, may have resented having a black boss.

Watch Alexander’s reaction in the clip above and her full story during tonight’s episode of "Finding your Roots with Henry Louis Gates Jr."