Authorities say a U.S Forest Service firefighter has been killed following a helicopter crash in Montgomery County. The Texas Department of Public Safety says the helicopter crashed Wednesday afternoon east of the Grimes County community of Richards near Bethel Road and FM 149 in northwest Montgomery County. Two other individuals were injured in the crash and taken to a hospital in nearby Conroe. Their condition is stable. No names have been released. DPS says the crash took place during a controlled burn operation in the Sam Houston National Forest. The helicopter was a 2009 AStar 350. The cause of the crash was not immediately known, but the Federal Aviation Administration and the National Transportation Safety Board will investigate the crash.