An Air Force civil engineer was killed Sunday when the Marine Corps helicopter he was riding in crashed in Iraq's Anbar province, the Defense Department reported Tuesday.

Capt. Kermit O. Evans, 31, was assigned to the 27th Civil Engineer Squadron, Cannon Air Force Base, N.M., where he was a member of the explosive ordinance flight. He was deployed to the 732nd Expeditionary Mission Support Group, part of the 332nd Air Expeditionary Wing.

In Iraq, Evans' home base was Camp Victory in Baghdad, where he was the operations officer for the group's Detachment 5 weapons inspection flight.

Evans was killed along with three other U.S. troops when a CH-46 Sea Knight helicopter with 16 people onboard made a forced landing into a lake, the military said. The twin-rotor helicopter experienced undisclosed mechanical problems while flying over Lake Qadisiyah.

The pilots flew the helicopter close to shore before setting it down, according to reports.

The pilots maintained control of the aircraft the entire time, the military said.

A dozen people survived the crash. A Marine was pulled from the water, but he could not be resuscitated. Evans' body and those of two other troops were found in a subsequent search, the military said.

Evans joined the Air Force in 2001 after graduating from Mississippi State University. He was promoted to captain in 2005, a family member said. This was his second tour to Iraq.

Survivors include his wife, Pernetha Evans, their 13-month-old son and a brother who is also in the Air Force.