A peculiar chapter of Colorado's criminal history was closed on March 9, 1971, with the announcement that Gloria Tannenbaum, suspect in two deaths and one disappearance, had died in the state mental hospital at Pueblo. A suicide note was found at her bedside, and authorities concluded she had somehow managed to ingest a dose of cyanide -- the same poison allegedly used to kill two of her victims in 1969. Gloria Tannenbaum's publicized troubles began after Dr. Thomas Riha, 40-year-old professor of Russian history at Colorado University, vanished from his home near the Boulder campus on March 14, 1969. Within a short time, Tannenbaum was charged, both in Boulder and Denver, with four separate felony counts involving illegal disposal of Riha's property. Prior to her trial on one charge -- that of forging his name on a $300 check -- Gloria was pronounced insane by court psychiatrists and confined to the state hospital until such time as she recovered sufficiently to participate in her own defense. In confinement, Tannenbaum boasted of influential contacts and hinted at "secret assignments" performed on behalf of intelligence agencies. Outside her narrow world, the search for Dr. Riha's body yielded no results, but homicide detectives had begun suspecting Gloria in two more deaths. A couple of her neighbors, 78-year-old Gustav Ingwerson and Barbara Egbert, 51, had recently died of apparent cyanide poisoning. There was insufficient evidence for indictment, but police believed that Gloria had murdered both, perhaps because they had possessed some information on the Riha case. The deaths and disappearance are officially unsolved, but Gloria appears to have claimed the last word on the case for herself. "It doesn't matter really," she wrote to her attorney on the last night of her life, "but I will tell you this. I didn't do Tom or Gus or Barb in. I went nuts with hurt over losing them. Everything that has made me feel good about myself has been taken away. Life is very cheap."