Following a team workout on Monday, Sept. 16, 12 members of the university men’s lacrosse team were diagnosed with rhabdomyolysis (rhabdo), a potentially life-threatening muscle disorder, the Washington Post reported. Five of those players required hospitalization, university spokesperson Patrick Collins said in an update on Saturday, Sept. 21.

After nine men’s lacrosse players were hospitalized with serious medical conditions following a workout led by a recent Navy SEAL graduate, Tufts University says they’re appointing an independent investigator to figure out what happened.