Philip Christian tells local media that his 39-year-old brother, Staff Sgt. Eric Christian of Warwick, and another Marine were training Afghan soldiers when one of them turned on the Americans and shot them during a patrol.

The Pentagon on Monday confirmed that Christian and 23-year-old Cpl. David Sonka of Parker, Colo., were killed Saturday during combat operations. They were members of a Marine Corps Special Operations Battalion based at Camp Lejeune, N.C. Military officials haven’t released details, saying the deaths are being investigated. Christian grew up in Poughkeepsie and graduated from high school in Ramsey, N.J. His mother lives in Warwick, on the New Jersey border.

Base officials confirmed Monday that two Camp Lejeune Marines were killed over the weekend in Farah province, Afghanistan.

With the circumstances of the incident still under investigation, base officials would not confirm whether the two MARSOC Marines are the same Marines who were killed by insider attacks on Saturday in the same location.

Christian, 39, of Warwick, N.Y. was a veteran of both Iraq and Afghanistan whose decorations include the Joint Service Achievement Medal, Navy and Marine Corps Achievement Medal, two Army Achievement Medals, two Good Conduct Medals and a Combat Action Ribbon. Sonka’s decorations include a Navy and Marine Corps Achievement Medal, Good Conduct Medal and a Combat Action Ribbon.