A state trooper shot and killed a 16-year-old armed with a knife and airsoft gun, Maryland authorities say

A 16-year-old, armed with a knife and what turned out to be an airsoft gun, was shot and killed Tuesday afternoon by a Maryland state trooper, a state police official said.A 16-year-old, armed with a knife and what turned out to be an airsoft gun, was shot and killed Tuesday afternoon by a Maryland state trooper, a state police official said.