NEW YORK — It might have been the single ghastliest moment on a drama last season: On the finale of "The Shield," Detective Shane Vendrell executed his partner, Detective Curtis Lemansky, with a hand grenade.

Not that Shane didn't have his reasons. He was scared Lem would fold under pressure to spill secrets about their L.A.P.D. Strike Team, sordid secrets that could land all those renegade lawmen in the slammer. Clearly, Lem needed to be saved from betraying his comrades.

But that doesn't mean Shane isn't bummed out about his evil deed. At the same time, his status among fans of this gritty FX drama has plummeted from vigilante hero to TV's biggest skunk.

"The most hated character on television?" chortles Walton Goggins, who plays Shane. "I like to think he's the most misunderstood."

Either way, viewers will be riveted as "The Shield" begins its sixth season tomorrow, with Strike Team leader Detective Vic Mackey vowing to identify and pay back Lem's killer — little dreaming it's his closest compadre.

"We need the truth," growls Mackey (series star Michael Chiklis) to Shane, adding, "This thing's gonna get a lot uglier before it gets better."

This is a juicy story arc for Goggins, who, as the season unfolds, will get to play grief, self-loathing, even a death wish. "Part of Shane wants to get caught and pay for everything he did," Goggins says.

Meeting with a reporter in New York, Goggins displays Shane's expansive grin and wiry frame. Notably absent: Shane's hotheaded, hot-dogging personality.

The 35-year-old Goggins is a warm, easygoing chap, who grew up outside Atlanta and excelled in competitive hog-calling and, as a child teamed with his mother, was a state clog-dancing champ.

As a youngster he landed film work in Atlanta, then, at 19, made the leap to Los Angeles.

Since then, he has appeared in features including "The Apostle," "The Bourne Identity" and "The World's Fastest Indian." With his partners at Ginny Mule Pictures, he shared a 2001 Academy Award for the short film, "The Accountant," which he produced and starred in.

Meanwhile, "The Shield" (already renewed for a seventh season) will keep him on the run — literally and figuratively.

Boiling in its murky moral climate, this Peabody Award-winning drama has a raw, kinetic narrative style that never sits still, and seldom gives its actors a break.

Goggins marvels at the show's on-the-fly shooting regimen, often on some of L.A.'s meanest streets.

"Most actors are concerned with hitting their marks. We're concerned with not getting hit by cars," he says. "Except for just a few extras put in here and there, what happens on those locations for the most part is real. We don't always know what's gonna happen."

One thing Goggins didn't know would happen: the extreme reaction to Shane's assassinating poor Lem. Goggins has taken plenty of heat for it, and not just from viewers.

"It was so weird showing back up to shoot this season," he says. "Maybe I was kind of projecting on the situation, but people on the set were treating me differently! The craft service guy didn't make me a damn coffee. Everybody else got a coffee, 'cept for Walton!

"And everybody's going, 'Oh, there's the guy responsible for Kenny not being here.' "

"Kenny" is Kenneth Johnson, who had played Lem since the series began in 2002.

But here it gets weirder: In real life, Goggins and Johnson are best friends. They met filming "Major League: Back to the Minors" a decade ago.

Weirder still: They filmed last season's killing scene just days after getting back from a weekend in Detroit at the 2006 Super Bowl. Johnson had scored a couple of tickets and invited Goggins along.

"We had the best time!" says Goggins. "But it was also bittersweet. We did all these interviews and people kept asking, 'What's gonna happen?' And we couldn't say a word."