WASHINGTON  A gentle snow fell on the funeral of Staff Sgt. David Senft at Arlington National Cemetery on Dec. 16, when his bitterly divided California family came together to say goodbye. His 5-year-old son received a flag from a grateful nation.

But that brief moment of peace could not hide the fact that for his family and friends and the soldiers who had served with him in the wars in Iraq and Afghanistan, too many unanswered questions remained about Sergeant Senft’s lonely death in a parked sport utility vehicle on an American air base in Afghanistan, and about whether the Army could have done more to prevent it.

Officially, the Army says only that Sergeant Senft, 27, a crew chief on a Black Hawk helicopter in the 101st Airborne Division’s aviation brigade, was killed as a result of “injuries sustained in a noncombat related incident” at Kandahar Air Base on Nov. 15. No specific cause of death has been announced. Army officials say three separate inquiries into the death are under way.

But his father, also named David Senft, an electrician from Grass Valley, Calif., who had worked in Afghanistan for a military contractor, is convinced that his son committed suicide, as are many of his friends and family members and the soldiers who served with him.