(KTRS)  The Missouri Highway Patrol says four people were killed late this morning in a head-on collision on Interstate 64 near Lake St. Louis in St. Charles County. According to the patrol, a truck crossed the median of Highway 40 into oncoming traffic. Westbound lanes of highway 40/64 are closed, traffic is being diverted onto Winghaven. In addition to the four fatalities, a fifth person is being treated for injuries, their condition is not known.