The death of a Black 17-year-old in a juvenile detention center in the Midwestern US state of Kansas was a homicide, according to a new autopsy report.

Cedric Lofton, a young man who was taken in custody on suspicion of battery against police officers and held at the Juvenile Intake and Assessment Center in the city of Wichita, died on Sept. 26 from "complications of cardiopulmonary arrest sustained after physical struggle while restrained in the prone position," KWCH12 news reported on Tuesday, citing the Sedgwick County medical examiner ruling from Monday.

Following an altercation with staff members on Sept. 24, Lofton was taken to a local hospital and died two days later.

The autopsy “indicates Lofton had been lying face down for as many as 39 minutes when juvenile facility staff realized he had no pulse. The document says he was shackled and handcuffed," said the local TV station.

The attorney for Lofton’s family released a statement saying the autopsy "confirmed" their belief that the juvenile facility staff "killed" Cedric.

"As supported by the video evidence, these individuals unjustifiably and with excessive and unreasonable force pinned Cedric to the ground, ultimately killing the unarmed, 135-pound, 17-year-old African American teenager,” said the statement.

His family believes prosecutors “should pursue criminal charges against the law enforcement personnel responsible for Cedric’s death," it added.

Cedric’s death was caused "by the hands of the very authorities that were obligated to protect him and make sure he was safe," said the lawyer.

"Instead, they killed him with conscious disregard for the young life in their keeping,” it added.

While the staff members involved in the case have not been identified, local authorities said they are on paid administrative leave.

In a statement, local District Attorney Marc Bennett stressed that his office is reviewing the autopsy, adding that a "lengthy investigation" was launched by the sheriff's office and the Kansas Bureau of Investigation./agencies