"The Killing" season finale: The killer to be revealed

(CBS/AP) The season finale of "The Killing" airs this Sunday and according to Joel Kinnaman, who plays Detective Stephen Holder, he and Detective Linden will finally crack the case.

The big reveal comes not a moment too soon for restless viewers, some of whom thought they were promised who did it a year ago but got a cliffhanger instead.

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"It was a little bit of mismanaged expectations, marketing-wise," says Kinnaman, "so some people felt tricked."

Even so, the time has come on this heavy-hearted whodunit to find out Who Killed Rosie Larsen.

But whoever the culprit turns out to be, one thing has been clear since the series premiered: Holder - an ex-narc and recovering addict - is an endearing eccentric infused by Kinnaman with grit, nuance and the lone measure of comic relief in a series that otherwise is shrouded in gloom.

Another thing is sure: Holder isn't the killer.

The 32-year-old Kinnaman scrunches his face dismissively at such a notion: "That would just be stupid," he says. "And it's not a stupid show."

What did he think when he learned who did the deed?

"I was surprised," he allows. "Yeah, it was cool. It was very satisfying."

"The Killing" was the Swedish-born actor's first American job and he found that the show was far from thought Hollywood would be, especially his co-star Mireille Enos, who plays Detective Sarah Linden.

"She leads with generosity, and her vanity is nonexistent. She brought out the best in me," Kinnaman says of Enos.

"We have a similar perspective on storytelling," Enos said. "We both believe that weird, awkward humanity is more interesting than things in nice packages."

As TV's most awkward but delicious odd couple, their matchup was casting kismet: Before each was signed, they had never even read together.

"We met each other on the plane up to Vancouver to film the pilot," Enos said, "and by the end of that flight, we were pals."

But as the season finale of "The Killing" nears, with its resolution of a mystery stretching back to its premiere, the future of the series remains a mystery. AMC has not yet said if the show will be renewed.

When asked about that, Kinnaman looks unperturbed.

"I'm planning on doing the third season of 'The Killing,'" he declares with a determined smile. "I'll go up there and shoot it myself."

The finale will air Sunday night at 9 p.m. ET/PT on AMC.