Insomnia ending explained (spoilers)

[Antonioliz]

At a dock, Engstrom and Jon Holt confront each other and Holt says that Tanja's death was an accident. Holt runs away from Engstrom, he slips, hits his head and falls into the water. Engstrom goes to the house near the dock (the house seen in that photo where Jon Holt has a fish in hand) and finds Tanja's dress, evidence that Holt did kill Tanja and that the two of them would hang out in that house. Hilde tells Engstrom that she knows that he shot Vik.

[dustin]

Walter Finch (Robin Williams) is revealed to be the girls murderer. Ellie (Hilary Swank) figures this out from looking in one of Walters books that Ellie had, and finding his autograph inside. She also finds the shell casing from the shot that killed Hap and puts everything together. Ellie goes to Walters cabin to look for him, but she is met by a hail of gunfire. Will (Al Pacino) reveals to Rachel (Maura Tierney) that he was guilty of falsifying evidence by planting a drop of blood, and this was part of his guilty conscience. Still suffering the effects of sleep deprivation, he finds out Ellie went to the cabin, and drives after her. He hallucinates almost crashing into an imaginary truck. When he gets there, he tells Ellie to give him covering fire so he can get inside the cabin. Dodging a hail of gunfire, Will slips under the cabin and rushes inside. You forgot the wild card, Will says Walter, before shooting Will with a pistol. Will recoils from the shot and fires a shotgun blast, killing Walter and knocking him into the water, where he slowly sinks. Will, gravely injured, goes outside and lies down on the dock, confessing to Ellie that he shot his partner but hes not sure if its an accident or on purpose any more. She takes out the shell casing that would incriminate him, and she tries to throw it into the lake. He grabs her arm and stops her. Dont lose your way, says Will. He closes his eyes. Let me sleep. Ellie calls for an ambulance, but its already too late. Will Dormer dies lying on the dock, finally at rest.