The Daily Camera reports six women reported they believed they were drugged Oct. 17 at parties at four different fraternities near the school’s campus in Boulder.

According to police reports released last week, three of the women were treated at Boulder Community Health’s Foothills Hospital and had blood samples taken as part of their treatment. Police later served a warrant for those samples but the testing laboratory said they contained a “gel clot activator” that interfered with the testing equipment.

Boulder Community Health says it hasn’t heard of its blood samples being rejected in police investigations before.