JOHNSTOWN, Pa. — Despite swirling reports of federal investigations of a half-dozen companies close to him, Rep. John Murtha (D) returned as a hero to his hometown Thursday, hosting his annual convention for contractors doing business in Pennsylvania’s 12th district. The hockey arena where Paul Newman’s classic “Slap Shot— was filmed is draped with balloons and bunting, and the floor is covered with exhibits mounted by companies that have thrived off Murtha’s largess.And Murtha’s defenders argue there is nothing wrong with any of it.“Mr. Murtha is the best of the best in the world,— said Bill Kuchera, whose Kuchera Defense Systems has received millions of dollars in earmarks and was raided by federal agents in January.John Polacek and his brother William run a welding company that gets no earmarks, but does a booming business working for other companies that do. They argue that Murtha has done exactly what a Member of Congress is supposed to do — bring economic opportunity to a struggling district.“It’s stimulus — money stimulus and relationship stimulus,— John Polacek said.The money stimulus is earmarks that Murtha provides for small companies that otherwise would not get an opportunity to compete for federal contracts. The relationship stimulus is the annual Showcase for Commerce in the hockey arena and other events that Murtha arranges to introduce small companies to large, established contractors.William Polacek said: “He gets us the introductions, they give us opportunities, we provide a quality product on time. ... What the heck is wrong with that?—The drumbeat of critical stories does not seem to have dampened the enthusiasm of the Showcase crowd for Murtha. He visits every exhibit in the arena and is greeted with hugs and warm handshakes at all of them.Shawn Piatek, the public relations director for the Showcase — this is the first time the event has had such a director — said attendance is as high as ever. About 2,000 people are attending, he said, and the 200 or so exhibit spaces are sold out as usual. There also was not a free hotel room in Johnstown Thursday night, and towns 20 miles away were flooded with Showcase attendees.