BEIJING, July 19 (Xinhuanet) -- An expert said an estimated 40,000 people in the United States are involved in professional dogfighting, a blood sport banned in all the nation, according to media reports Thursday.

    Atlanta Falcons quarterback Michael Vick and three other people were indicted Tuesday by a federal grand jury on charges related to illegal dogfighting, exposing an underworld of cruelty to animals.

    The indictment alleges that the 27-year-old Vick and his co-defendants began a grisly dogfighting operation in early 2001 in which dogs fought to the death -- or close. Losing dogs were sometimes killed by electrocution, drowning, hanging or gunshots.

    If convicted, Vick and the others could face up to six years in prison, 350,000 U.S. dollars in fines and restitution.

    However, dogfighting is "far more pervasive than people think" and the nightmare of dogfighting is growing, said John Goodwin, an expert on animal fighting with the Humane Society.

    There are an estimated 40,000 professional dogfighters in the United States, who putt on fights and buy and sell fighting dogs, Goodwin said.

    An additional 100,000 people are involved in "streetfighting" -- informal dogfighting, he added.

    Dogfighting is illegal in all 50 states. It's a misdemeanor in Idaho and Wyoming, and a felony in all other 48 states.

    Despite the laws, dogfighting is big business. Goodwin said it's impossible to estimate the amount of money involved, but the purse for a top-level professional fight could be 100,000 U.S. dollars.

    (Agencies)