So my theory was wrong, Mayor Adams was not the killer. At first it appeared it was Jamie (Eric Ladin), Richmond's political aide.
"It was an accident," Jamie finally screamed at Richmond. A flashback showed Jamie scheming with an Indian leader to disrupt Mayor Adams' waterfront project to help boost Richmond's propsects for winning the mayor's race election. Rosie's phone rang, alerting Jamie to her presence. He smacked her, panicked and put her in the trunk of a car. Rosie was just in the wrong place at the wrong time.
"I was only thinking of you," Jamie told Richmond. "Hey, I didn't want to do it. But when something needs to be done, I do it."
Holder (Joel Kinnaman) and Linden (Mireille Enos) arrived on the scene. Jamie pulled a gun and aimed at Linden. Holder fired, killing Jamie.
But wait, there's more!
Rosie's Aunt Terry (Jamie Anne Allman) -- sister of her mother, Mitch (Michelle Forbes) -- was the actual, if inadvertent, killer. She didn't know it was Rosie she was murdering. After Jamie put Rosie in the trunk of a car, Terry sent the car into a lake for the benefit of some married man she was sleeping with, a character I don't recall seeing previously, although, as I said, I skipped some episodes because "The Killing" got tedious.
I loved the concept of "The Killing" and the look of the pilot. But the plotting and writing did not live up to that pilot episode with too many red herrings and misdirects -- and a lot of wasted time as the show meandered over two dozens episodes to get to revealing the identity of the killer.
Although AMC had suggested the finale would open up another murder investigation, that didn't really happen.There's a reference to a body found by the airport, but the episode sure felt like a series finale. I don't think it will be back but Joel Kinnaman may well go on to become a star. And Enos deserves another shot with better writing.
The Hollywood Reporter has an interview with Allman about being the killer.