Seven people accused of conspiracy in a $1.6 million Brink's holdup attempt a year ago were charged with plotting a dozen other crimes, including the 1979 prison escape of Joanne Chesimard.

The alleged crimes--armored-car holdups, attempted robberies and threats to murder federal informants--go back to 1976, according to an indictment handed up by a federal grand jury in Manhattan.

Chesimard, 34, is believed to be the "soul" of the Black Liberation Army. She has not been accused or named as a suspect in the Oct. 20, 1981, heist in Nanuet, N.Y., in which a Brink's guard and two Nyack police officers were killed. But she shares a common background with the Brink's suspects: members of the Weather Underground and the Black Liberation Army who allegedly financed their terrorist activities through robberies.

The indictment accuses four of the seven with participating in Chesimard's escape from a New Jersey prison where she had been serving a life sentence for murdering a state trooper in 1973. She remains at large.

The seven people named are Sylvia Baraldini, a legal aide; Mutulu Shakur, the suspected mastermind of the Brink's heist; Susan Rosenberg, a fugitive; Nathaniel Burns, a reputed BLA soldier; Edward Joseph; Cecil Ferguson, and Cheri Dalton.