Which sections of the antitrust laws might have been violated by Mylan and other generic drugs producers?

A congressional inquiry report says the price of doxycycline, a generic antibiotic used to treat acne (and other things), rose more than 8,000 percent in 2013–2014. Doxycycline is made by Mylan, one of several generic drug manufacturers that are under investigation by the Justice Department because their list prices of many older medications have risen in lockstep in recent years.