A wide-ranging investigation into generic drug prices took its most significant turn yet on Thursday, as state attorneys general accused two industry leaders, Teva Pharmaceuticals and Mylan, and four smaller companies of engaging in brazen price-fixing schemes - and promised that more charges were coming. A civil complaint filed by 20 states accuses the companies of conspiring to artificially inflate prices on an antibiotic and a diabetes drug, with executives coordinating through informal industry gatherings and personal calls and text messages. Officials said the case was a small example of broader problems in the drug business. We believe that this is just the tip of the iceberg," George C. Jepsen, Connecticut's attorney general, whose office started the inquiry that led to the charges, said. "I stress that our investigation is continuing, and it goes way beyond the two drugs in this lawsuit, and it involves many more companies than are in this lawsuit." The complaint on Thursday describes a cozy industry culture defined by regular dinners and social outings, and argues that those events often cross the line to violate antitrust rules. Generic drug makers hoping to begin selling a new drug first seek out rivals, the suit says, in hopes of reaching an agreement on how to maintain market share and avoid competing on price. "These agreements had the effect of artificially maintaining high prices for a large number of generic drugs and creating an appearance of competition when in fact none existed," the lawsuit says.