Top left: After the investigators' meeting, Brian Zeller indicates to Will that he wants to see him. Will and Zeller must have met not long after this, and during this meeting, Brian told Will something that led him to conclude that the incest between Molly and Kevin was occurring. The point is that Will initially found out about the incest from Brian. Top right: The fact that Will knew about the incest occurring between Molly and Kevin, prior to the Graham family being relocated from Captiva, is indicated by the fact that at the beginning of the relocation scene, while the Graham family is walking up to the front door of their new (temporary) residence, Kevin is walking close to Will and at a distance from Molly - it is as if Will is trying to 'guard' his son against her, implying that he considers her a danger to Kevin. Above left and right: Kevin himself feels no sense of danger from his own mom, as indicated by the fact that when Will suggests to Kevin that he run down to the dock, Kevin says, "I wanna hang around here. I'm in the kitchen, mom." - as if Molly needs protection from Will.
As indicated in part 49 of the analysis, Molly admits to Will while at the new location, that she is Kevin's natural mother and that she has been having incest with him. What prompted her into these admissions is that Will confronted her about the incest, which as stated abovve, he found out about from Zeller.
