Megan Marshack, who as a young aide to Nelson A. Rockefeller found herself at the center of sensational conjecture about the circumstances of his sudden death in 1979, died on Oct. 2 in Sacramento. She was 70.

Her death, at a live-in medical facility, was announced in an obituary that her brother, Jon Marshack, said she had written herself last year and that was posted by a Sacramento funeral home on its website. Mr. Marshack, her sole immediate survivor, said the cause was liver and kidney failure.

The obituary represented Ms. Marshack’s first public comment about Mr. Rockefeller, the former Republican vice president and New York governor, since she witnessed his death, also at 70, on Jan. 26, 1979. Ms. Marshack, who was widely believed to have been romantically involved with Mr. Rockefeller had for decades remained silent about the circumstances of the death.

In its aftermath, she found herself in the odd position of a journalist avoiding journalists. As an editor of syndicated television news, she wished not to be in the spotlight herself, but reporters followed her on the street and even into the subway, hoping she would say something about Mr. Rockefeller’s last night.

Ms. Marshack’s self-written obituary disclosed some previously unreported details about her association with Mr. Rockefeller but did not mention a romance — although it ended suggestively, quoting from the 1975 musical “A Chorus Line.” Ms. Marshack wrote that she “won’t forget, can’t regret what I did for love.”

The initial account of Mr. Rockefeller’s death was supplied by Hugh Morrow, his longtime spokesman, after midnight on Jan. 27. He told The New York Times that Mr. Rockefeller had died instantly, at 10:15 p.m., while he was in his office, alone with a bodyguard, “having a wonderful time” working on an art book he was writing.