An 18-year-old woman collapsed and died Tuesday at a Navy boot camp in Illinois, after a similar death in February that also followed physical exertion.

Kelsey Nobles, of Mobile, Ala., died of cardiac arrest after a physical fitness test, her father Harold Nobles told WKRG-TV.

Another young woman, 20-year-old Kierra Evans, died Feb. 22 after collapsing following the running portion of the Navy's Physical Fitness Assessment.

Nobles' father said he's concerned about the fact that his daughter is the second woman to die recently at the Recruit Training Command in Great Lakes, Ill.

"She was just full of energy. She would give anyone anything, her last her dollar. She was the sweetest soul," her father told the local station. "For me, I'm just like what's wrong? These young people are so excited about serving their country and going into the military. Are they doing enough to check them? Does physical testing need to be more in-depth?"

A spokesman said the Navy is investigating events leading to Nobles' death.