Through all attempts to cover his tracks — secretive lingo, coded Internet chatter, a move from Pennsylvania to Texas — Thomas Weigner was intently pursued by a vigilant group of animal-loving sleuths.

For years, they suspected him of being a bigwig in dog fighting’s shady underworld, a breeder and trainer of fearsome canines who willingly would rip each other apart for the amusement of their bloodthirsty masters.

But it was hard to get close to Weigner. He made sure his inner circle was limited to family and trusted friends, though he seemed to live a normal life at a well-kept brick home and 24-acre spread in rural east Texas.

Then, in the middle of a warm August night, everything came crashing down. No, it wasn’t a group of warrant-wielding lawmen who invaded Weigner’s sanctuary, looking to find the telltale signs of animal abuse and slap the cuffs on him.

These were masked, fatigue-wearing gunmen who burst into the home. They tied everyone up and began rummaging through every nook and cranny, desperate to find the $100,000 in cash that Weigner supposedly collected after one of his top dogs whipped another grand champion.

By the time the invaders fled back into the night, Weigner was crumpled on the ground, bleeding to death from a gunshot just above his right knee.

Soon, the property was crawling with guys wearing badges. They were revolted at what they found when the sun came up. And they were shocked at just how far the case would lead.

“It was very much an eye opener,” said Greg Arthur, the sheriff in Liberty County, “as far as the dog fight industry and how big it actually is.”

Murder has a way of making people talk. When the Liberty County sheriff’s office began snooping for leads, they found a road that led in all directions. Pittsburgh. Atlanta. Los Angeles. Dayton, Ohio. Even Ecuador.

And they kept hearing one name in particular: Michael Vick.

“Ohhhh, yes,” said Liberty County sheriff’s Capt. Chip Fairchild. “When we were in Dayton, they mentioned it there. In Atlanta and Pittsburgh, too. They all knew about Michael Vick being into it and sinking big dollars into it. We kept hearing that over and over. That wasn’t a trail we needed to go down, because there was no indication that he had ever been here or knew our guy (Weigner). But our guy certainly knew people who knew Michael Vick.”

For many people, dog fighting wasn’t on the radar until Vick, star quarterback of the Atlanta Falcons, got swept up in it.

In April, when investigators raided a Vick-owned home in Surry County, Va., as part of a drug investigation involving a cousin of his, they stumbled upon a clandestine kennel out back.

Sixty-six dogs, mostly pit bulls, were seized, along with evidence of an organized fighting operation: treadmills rigged up for training; “break sticks” that are used to pry apart the powerful jaws of fighting animals; blood-soaked carpeting that might have been used in a fighting pit; veterinary medicines for treating wounds; and “rape stands,” hideous contraptions used to restrain female pit bulls during the breeding process.

Vick denied any wrongdoing shortly after authorities raided his home. Since then, he’s declined comment on the advice of his attorney.

Washington Redskins running back Clinton Portis quickly defended Vick’s right to be involved in dog fighting, saying “it’s his property; it’s his dogs.”

“If that’s what he wants to do, do it,” Portis said last month during a TV interview.

After coming under intense criticism from animal-rights groups and plenty of football fans, Portis apologized.

But Gabriel Jones, who grew up in rural Mississippi, e-mailed The Associated Press to say Portis, a native of Laurel, Miss., needn’t apologize. After all, Portis simply was conveying a fact of life on the back roads of his home state.

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“I know it’s fashionable for people to have a lot of indoor pets. You see people walking around with dogs in their purses, dogs as accessories, showing off their dogs. I just feel there’s a whole other side to it,” Jones said in a telephone interview. “In the South, at least where I came from, there’s no such thing as an indoor pet unless it’s a cat, maybe. People have dogs for two reasons: They are either guard dogs or fighting dogs.”

Although dog fighting might be associated largely with the backwater South, it’s actually a national phenomenon, cutting across geographic, social and racial lines.

The Humane Society of the United States estimates that at least 20,000 — and perhaps as many as 40,000 — are involved in contests ranging from impromptu, back-alley battles to highly sophisticated contests where the pots run into the six figures.

“It has started to become less a rural activity and more an urban activity,” said John Goodwin, who handles dogfighting issues for the national Humane Society. “It’s largely a recreational activity for gang members.”

Major city police forces, such as Chicago and Atlanta, have units dedicated solely to shutting down the countless underground bouts. Forty-eight states have made dog fighting a felony (Idaho and Wyoming are the exceptions), but there are loopholes.

In Georgia, for instance, dog fighting is a felony, but it’s not illegal to be a spectator or even to breed dogs with the purpose of fighting.

“You actually have to catch them in a fight,” said state Sen. Chip Rogers, a suburban Atlanta Republican who has tried unsuccessfully during the last two legislative sessions to toughen the law. “That’s why we have no one in jail for dog fighting.”