When a mysterious person with a hood appeared on The Sinner Season 2, you may have forgotten for a moment that you weren't watching Riverdale. But who the identity of the person in the hood on The Sinner may provide insight into why 13-year-old Julian poisoned Bess and Adam. This cloaked figure is slightly reminiscent of the masked person in The Sinner Season 1, who turned out to be the father of the man that Jessica Biel's Cora murdered on the beach. So while there is an obvious suspect for the person in the hood, the full truth about their identity probably won't be revealed until the season finale. But their appearance so early on in Season 2 is proof that Julian has had a sinister upbringing and that he isn't just a cold-blooded killer all on his own.
The Season 2 premiere showed Julian seeing the hooded figure twice. The first time was in the motel when Bess (who may or may not be Julian's mother) asked him about his recurring nightmare. Julian then had a flash of a hooded figure walking down a hallway and approaching a door as a blue light shone on them. Then, he saw the dark figure when he confessed to murdering Bess and Adam. Detective Harry Ambrose pled with the child for more information that could help his case. "You have to try and tell me," Bill Pullman's character said. Julian then stated, "My mother—" as he became distraught and saw the hooded figure with the blue light again. Julian didn't reveal anything else about his mom to Ambrose and broke into tears before he sadly asked, "Why can't I just go home?"
The Sinner Twitter account teases in the above video that this hooded figure will be back for the second episode. Julian lays motionless in bed as the person approaches and seemingly bends over to touch Julian. This scene is most likely a flashback or a vision of the nightmare that Bess alluded to. Either way, it seems like this hooded figure is associated with a traumatic event that happened in Julian's past that haunts him.
As for who the adult in the hood is, the most suspicious character is Carrie Coon's Vera. Julian pictured the hooded figure after he mentioned his mother to Detective Ambrose and Vera claimed to be his real mother at the end of the season premiere. Of course, this theory only works if you believe that Vera is actually Julian's mother — and at this point, it's smart to be dubious about that claim. But even if she's not Julian's birth mom, she is associated with a blue light. Julian's flashback of a session with Vera had her using a clicking speaker with a blue light (perhaps a hypnosis machine?). That blue light is reminiscent of the blue light that shines on the person in the hood as they walk through the doorway. As the below photos show, the image of Vera standing next to the machine actually mirrors where the hooded figure is in relation to the blue light.
However, The Sinner still has seven episodes to go in this season. And based on the first season, it seems too obvious an answer for the person in the hood to be Vera. So it's important to consider the other suspects so far. Since Bess directly asked Julian about the nightmare, it doesn't seem like she would be the one in the robe. And while Adam could be in the robe, the person doesn't seem tall enough; the height of the figure just might indicate that it's a woman.
One character who audiences haven't gotten any information on yet, but should be considering, is Hannah Gross' Marin. USA teased that Heather's high school best friend Marin went missing years ago. Previews show that she got mixed up with Vera's cult-like community and showrunner Derek Simonds emphasized to Variety how vital Marin is to this season. He referred to her as the Laura Palmer of The Sinner, a reference to the iconic Twin Peaks character whose murder the entire show hinges upon. "It's actually [Marin's] narrative and what happened to her that all of the other character perspectives are revealing," Simonds said. So perhaps this character who is already cloaked in mystery is also literally wearing a hooded cloak.
Even if Vera is the woman in the hood, why that figure is approaching Julian is probably something that viewers won't be able to figure out just yet. But based on the limited information that The Sinner has provided so far, Julian is fearful of this figure and that might mean they are the force behind his murderous actions.