ST. PETERSBURG, Fla. (AP) — The businesses under investigation in a Florida gambling probe started popping up in strip malls about six years ago and rapidly spread.

The unregulated, unlicensed stores became a billion-dollar enterprise, but authorities say one of the industry's biggest players was toppled this week. About 50 people were arrested in a handful of states, many of them charged with racketeering and conspiracy.

They were all linked to Allied Veterans of the World, a charity accused of masking a $300 million illegal gambling ring.

Allied Veterans had about 50 locations, but by some estimates there are 1,000 similar storefronts across Florida. Authorities say these so-called Internet cafes are actually small casinos with slot machine-style games. They have also popped up in Ohio, North Carolina, South Carolina and elsewhere.