Despite their accusations against each other, the girls had an unfathomable connection. During the trial, according to Sereny, "their heads turned toward each other, their eyes locked, their faces suddenly bare of expression and curiously alike, they always seemed by some sort of silent and exclusive communion to reaffirm and strengthen their bond." Yet they had their moments of betrayal: "They shook their heads incredulously or furiously at what one or the other said; they turned abruptly, glaring at each other when hearing themselves quoted as having accused the other of something outrageous; and they commented audibly -- in Norma's case with tears and desperate cries of 'No, No'; in Mary's case with loud and furious remarks -- about and against each other's evidence." Eventually the judge prohibited contact between the two girls during the trial.
Both denied any responsibility for Martin Brown, but both acknowledged they had been together with Brian on the day he died. According to Mary, a maniacal Norma strangled Brian. When asked if she was afraid that Norma might kill her, Mary boldly replied, "She would not dare -- Because I would turn around and punch her one."
Norma's grim version of the events, however, were closer to the truth: "May [Mary's nickname] told Brian to lie down," and then "started to hurt him." Norma demonstrated how Mary pinched Brian's nose. He started turning purple and tried to push Mary's hand away. "When she was really hurting him she said, 'Norma, take over, my hands are getting thick.'" But Norma left, she tearfully claimed, while Brian was still alive. She then went to her friend's house, where they made pom-poms (an odd activity after witnessing murder.) If Norma was truly disturbed by Mary's behavior, why did she return with Mary to make marks on Brian's body? Mary brought scissors with her because she wanted "to make him baldy." She also had a razor blade to cut into Brian's belly.