 Journalists such as <unk> <unk> attributed the split to <unk> and other <unk> members dividing over opposition to the <unk> brothers because of their alleged involvement in the execution of Anna <unk> <unk> in December 1975 , who was then the highest @-@ ranking woman in <unk> but had been suspected of being an informant . It was a year in which other FBI <unk> had been discovered in <unk> . On November 3 , 1999 , <unk> held a press conference in Denver , Colorado in which he accused the <unk> brothers of <unk> in <unk> 's death , and named three lower @-@ level <unk> members involved in her death : <unk> Looking Cloud , John Graham , and <unk> Nelson Clark . This was the first time that an <unk> leader active at the time of the <unk> murder had publicly accused <unk> of having been involved . 
