In the book, Meredith is the murderer, but the show came up with a completely different "who killed Harry's mom" storyline.
Adaptational Heroism: Bosch tears into Annette for not reporting what she knew, but she's certainly not as bad as her book counterpart from The Last Coyote, Meredith Roman.The episode, and the season, ends with Bosch standing at Dave Aronson's grave, snarling "You got away with it." It turns out that Epperson relocated to Morro Bay under the name "Dave Aronson"-and he died two years ago. It turns out that one of the Narcotics cops handling Mitchell/Epperson back in 1979 was none other than Irvin Irving. However, Martin Weiss, the Marks family's crooked attorney, has tracked her there, and he makes a call. Layla is there, spending some of her four million dollars of Mafiya money at a resort.
Near the end of the episode the scene cuts to the coast of Spain. Bosch and Edgar duck for cover, but Nash has grenades-and that's how he dies, when he pulls the pin on a grenade only to drop it when Harry wings him with a shot. Bosch and Edgar are walking up to the front door when Nash starts shooting with a submachine gun. The hunting preserve is now out of business but Bosch and Edgar still go to check it out.
The serial numbers lifted off of the weapons recovered from the bank shootout reveal that Carl Nash bought them all legally, then sold them to a hunting lodge up in the mountains, where he then "stole" them, resold them to his crew, and pocketed the insurance money.