Kendrick Johnson's schoolmates subpoenaed in "mat death"

A federal grand jury investigating the death of Kendrick Johnson, the Georgia teen found dead inside a rolled-up wrestling mat in his school gymnasium last January, has subpoenaed the teen's former schoolmates and their parents, Ben Crump, an attorney representing the Johnson family, confirmed to CBS News' Crimesider Friday.

The development was first reported by CNN Thursday afternoon.

Current students at Lowndes High School and current and former students at Valdosta High School were seen entering the federal courthouse in Macon on Thursday, according to the network.

The 17-year-old Johnson was found dead inside a rolled-up wrestling mat in the gymnasium of Lowndes High School in Valdosta, where he was a student, on January 11, 2013. Authorities initially called his death a freak accident, saying he fell head-first into an upright mat and became trapped. An autopsy conducted by the Georgia Bureau of Investigation (GBI) concurred.

The case was closed, but Johnson's family insists he was killed and had their son's body exhumed for a second autopsy last summer in which a private pathologist determined the 17-year-old died of blunt force trauma to the neck and that his body had been stuffed with newspaper.

In October, Michael Moore, the U.S. Attorney for the Middle District of Georgia, announced he was reopening the case and just last month, Johnson's parents filed a lawsuit against the funeral home that handled their son's remains, alleging the home intentionally disposed of their son's organs in an effort to interfere with the investigation into his death.

It is unclear whether anyone else was subpoenaed for the grand jury proceeding Thursday but CNN reports Lowndes County Coroner Bill Watson says that while he hasn't been subpoenaed, the FBI has interviewed him twice and he has spoken to the U.S. attorney. Johnson's parents reportedly say they have also spoken with the FBI.