In episode four of the docuseries, we see how retired detective Kevin Murphy looked into Berkowitz's associates at Untermeyer Park. Partaking in drug trading and sexual activities, Berkowitz's former associates called themselves the Children. It was difficult for Murphy to find people willing to talk to him since no one wanted to be implicated. He did, however, come across a man named John Paul, who was a high school freshman when John Carr approached him. According to Paul, the Children's activities were not initially serious, but he recalled a turning point where a ritual became much darker with dog killings.
A prisoner named Jesse Turner also divulged information about the murder of Ronald Sisman, who Terry believed was likely killed over a cult snuff film. Turner belonged to the Process Church cult and claimed that Sisman and a student named Elizabeth Platzman were killed by the cult, which had ties to the Children.
While these two confessions don't directly prove that Berkowitz had accomplices (in fact, detectives seemed pretty sceptical of them), they do show that Berkowitz was likely part of a more extensive cult network.