WILMINGTON, Del. (CBS) — Three teens have been charged in connection with the beating death of a high school student in Wilmington, Delaware.

The Delaware Department of Justice announced the charges on Monday against three girls in connection with the death of Amy Joyner-Francis, who died as a result of an assault that took place on April 21 inside the restroom at Howard High School.

Prosecutors said the medical examiner’s report played a key role in their decision on charges against the three minors. It was ruled that Joyner-Francis died from a cardiac incident that took place because of a pre-existing condition. It was determined that if the assault had not taken place, the cardiac incident would not have occurred.

Trinity Carr, 16, was charged with criminally negligent homicide. Authorities said Carr is the person who hit Joyner-Francis and sparked the injury that led to her death. Prosecutors said they would seek to have her tried as an adult due to “the severity of her offense,” which is punishable by up to eight years in prison.

Two other girls are facing charges of criminal conspiracy and will be tried as juveniles. Authorities said they lured Joyner-Francis into the bathroom, but did not physically assault her.

“What happened at Howard High School is a tragedy,” said Mayor Dennis P. Williams. “From the beginning, the Wilmington Police Department and the Department of Justice worked hand and hand to determine the appropriate charges. This is just the first step toward providing Amy’s family and our community with closure. As this process moves forward, I ask that we keep the family and loved ones of everyone involved in our thoughts and prayers.”

New Castle County Vo-Tech School District Superintendent Vicki Gehrt released the following statement:

“Now that the police investigation is complete and criminal charges associated with the death of the Howard High School of Technology student on April 21 have been announced by the Delaware Department of Justice, the school district will follow through with necessary actions for the students involved in the incident based on the school district’s Code of Conduct. Our responsibility is to follow school board policy and procedures for all students involved.”