A University of Wisconsin-Milwaukee student died in a campus pool Monday while he and his roommate were practicing swimming for an aquatics test for the U.S. Air Force, officials said.

According to a report by the Milwaukee County medical examiner's office:

Connor J. Driscoll, 19, of Madison and his roommate, Samuel Hemes, arrived at the UWM Klotsche Center pool on N. Downer Ave. about 7:30 a.m. Monday.

Driscoll wanted to practice for an aquatics test for the U.S. Air Force ahead of an entrance exam this week. Hemes and Driscoll, who were the only swimmers in the pool, began swimming laps in different lanes.

"(Driscoll) swam underwater the entire 25 yards and his roommate waited until he was done with that, (Driscoll) turned to the roommate and gave him the 'thumbs up,' " the report said. "At that point the roommate began swimming laps in his lane. At the same time, (Driscoll), at the deep end of the pool (14 feet) went underwater and was doing flips and somersaults, according to the lifeguard. He came up for air and then appeared to sink; there was no struggle."

The lifeguard noticed and immediately called for her partner, according to the report.

Lifeguards jumped into the water and Hemes helped them pull Driscoll out of the pool and attempted CPR. A medical team from the Milwaukee Fire Department also tried to revive Driscoll with a defibrillator.

The roommate told investigators that Driscoll was "an extremely skilled swimmer," the report said.

Authorities are investigating, but their initial belief was that the death is related to a health condition and not suspicious, UWM spokesman Tom Luljak said Monday.

According to the medical examiner's report, Driscoll's father said his son had never had any medical problems.

Driscoll's doctor said Driscoll was diagnosed with a bleeding disorder and sleep disorder in 2007. A cardiac test showed nothing abnormal in 2010.

Hemes told investigators that three to four weeks ago Driscoll had carried another person on his back, piggyback style, and tripped and fell to the curb, striking his face, but had not sought medical help at the time.

An autopsy is scheduled for Tuesday.

Luljak said Driscoll was a sophomore in the College of Letters and Science with an undeclared major and was living off-campus with two roommates.

He was working at the Aloft Hotel in Milwaukee and had just helped his father with a home rehab project on Sunday.