In a letter that Perry Smith's father writes to get him released from the Kansas State Penitentiary, he describes Perry's only remaining relative (besides himself) as a sister called Bobo, who lives with her husband. "Bobo" is a nickname for Barbara, also known as Mrs. Frederic Johnson. Perry also finds a letter that she wrote to him in which she tells him about her children and then writes that Perry's wrongdoings are not their dad's fault. She says, "What you have done, whether right or wrong, is your own doing." She believes that Perry is intelligent but that he must accept responsibility for his life and not blame their father for what has happened to him. Perry tells Dick that he "loathes" his sister and even wishes that she had been in the Clutter house so that he might have killed her. Perry Smith has lost contact with her sister at the time of the Clutter murders. She lives in a middle-class home in San Francisco, and she tells the detective not to tell Perry where she lives, as she's afraid of him. Perry and Dick told the police that they were with Perry's sister in Fort Scott on the night of the murders as an alibi, but Perry's sister does not live in Fort Scott.  

In his book In Cold Blood there are two Beverly's: Beverly Clutter the second oldest of the Clutter children (and one of the two surviving Clutters and Perry Smith's sister,  Beverly Johnson.  Beverly Johnson is Perry's only living relative.  Unlike all of Perry's other relatives who have succumbed to tragic fates, she seems to have escaped the family tradition and is married with two children. She is, however, afraid of her brother and keeps her address a secret from him.

Perry hates his sister and mentions to Capote he wishes she had been at the Clutter household the night of the murders. She attempts to contact him while he is in prison, but he does not maintain contact with her.