[NORTHERN MICHIGAN] Arianna Alioto, an 18-year-old redshirt freshman on Division II Northern Michigan, drowned in a pool at the school's Physical Education Instructional Facility after a team workout.

She was found unresponsive in the pool after the workout ended and her teammates left. After efforts to revive her, she was pronounced dead at a nearby hospital.

Investigators are looking into what caused her death and why she was alone in the pool.

Family friends told ABC 17 News in her hometown of Columbia, Mo., that Alioto may have had a medical emergency before falling into the pool.

“Arianna was not only a good soccer player, but a wonderful young woman. We felt honored that she chose to play at Northern Michigan University,” said Coach Matt Granstrand. “Our team and our extended team family are in extreme pain. It’s hard to grasp that Arianna was with us one moment and gone the next. It just doesn’t seem real. Her death is devastating.”

Alioto redshirted the 2012 season, but was expected to challenge for a spot up front next year.

"She made a huge impact, a lot of people loved her and i think that says a lot to what kind of person she was," her older sister, Sophia Alioto told ABC 17.

A memorial service will take place at 10 a.m. Saturday at the First Christian Church of Columbia.