A southwestern Illinois state trooper is facing a felony aggravated battery charge after authorities say he strip-searched a man along the side of a road during a traffic stop.  The Belleville News-Democrat reports 32-year old Cory Alberson of Swansea was released on $20,000 bail on Monday after he pleaded not guilty.  Prosecutors say Alberson pulled down a man’s pants during a traffic stop in January in East Saint Louis without the man’s consent.  The driver was never charged.  A spokeswoman for the Illinois State Police says Alberson has been relieved of duty.  The agency’s internal affairs division also conducted an investigation.  Alberson’s lawyer says the Swansea man denies any wrongdoing and plans to fight the charge in court.