Authorities say the body of a 19-year-old woman from Minnesota and student at Arizona State University was found dead Tuesday morning.
The Associated Press reports her boyfriend, 22-year-old Luis Soltero, is accused of her murder.
According to ABC15 in Phoenix, Rebecca Kasper was found handcuffed and beaten in a Tempe, Ariz., apartment complex just across the street from campus.
Police say Soltero walked into a police substation and told officers his girlfriend was dead.
Officers found Kaper's body in a bathtub, covered with blankets and coffee grounds, ABC15 reported. A plastic bag had been placed over her head. Kasper suffered from blunt force trauma to her head and face.
Court documents say Soltero admitted to killing his girlfriend in a written note found near Kasper's body, the Phoenix New Times reports. A bloody dumbbell that's believed to be the murder weapon was also found nearby.
Soltero was initially transported to the hospital after claiming he had spent 12 hours in his car with the engine running in a storage space.
Soltero is now being held in jail on $1 million bond.