One person was killed and another seriously injured in an accident early Monday morning in Madison County. Illinois State Police Officers responded about 2:00 o’clock this morning to the scene of a single-vehicle accident on Route 4 south of Highway 40 where a car swerved off Rt. 4 and struck a tree according to authorities. According to Illinois State Police, one person was killed and another person with critical injuries was flown to a hospital. No other details are available at news time.