CHARLESTON, W.Va. -- West Virginia's attorney general joined three other states and the District of Columbia to sue six generic drugmakers, alleging they conspired to hike prices for a common antibiotic and a diabetes medication.

Attorney General Patrick Morrisey said the allegations will be "pursued vigorously."

He joins attorneys general for Arkansas, Missouri, New Mexico and the District of Columbia in the suit filed Monday against Heritage Pharmaceuticals, Aurobindo Pharma USA, Citron Pharma, Mayne Pharma, Mylan Pharmaceuticals and Teva Pharmaceuticals.

It follows a nearly identical suit filed in December by Connecticut Attorney General George Jepsen, joined by 19 other states, based on Connecticut's ongoing investigation.

The six companies have asked Judge Vanessa Bryant to dismiss the initial lawsuit, denying they conspired to keep prices high for Doxy DR and Glyburide.