Mobile, Ala. — An 18-year-old Navy recruit from Alabama has died during boot camp in Illinois. Spokesman Lt. Joseph W. Pfaff says Kelsey Nobles, of Mobile, died Tuesday after collapsing during training at the Navy Recruit Training Center in Great Lakes, Illinois.

Nobles' father, Harold, told CBS affiliate WKRG-TV that doctors say she went into cardiac arrest. He says she passed out after her physical fitness test. He says she was taken to a civilian hospital where she was pronounced dead.

Kelsey Nobles graduated last year from Baker High School in Mobile, Ala. WKRG-TV

Nobles describes his daughter as a young woman who was "the sweetest soul" and "had the biggest heart." He says she was full of energy and would give anyone anything, even her last dollar.

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Pfaff says the Navy is investigating. This is the second death under similar circumstances at the boot camp in the past two months. According to the Military Times, Seaman Recruit Kierra Evans was pronounced dead at a hospital after she collapsed following physical training Feb. 22.

"For me, I'm just like what's wrong?" Harold Nobles told WKRG-TV. "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?"

The station reported that Kelsey Nobles graduated last year from Baker High School.

"Kelsey was highly respected and admired by her classmates, teachers and peers," the school said in a statement. "She made a remarkable impact on the Class of 2018 as well as Baker High School. Kelsey will be greatly missed."