WASHINGTON D.C. (Metro) -- The Pentagon says a Naval explosives expert from Des Moines was among the seven Americans who died last week in the crash of a Blackhawk helicopter in Afghanistan. Petty Officer Technician First Class Sean P. Carson was attached to an explosive ordnance disposal mobile unit out of San Diego. The Taliban claims responsibility for shooting down the helicopter, which also resulted in the deaths of four Afghans. Carson was 32 years old. Copyright © 2012 Metro Networks Inc.