Attorneys for the family of a 17-year-old student found dead in a rolled-up gym mat at a southern Georgia high school called on authorities Thursday to release surveillance video that they say could show what happened. 

Kendrick Johnson, they allege, was slain in January -- counter to authorities' conclusions that the three-sport athlete suffocated in the mat while reaching for a sneaker. 

"There is one eyewitness that we know is available -- it is the video recordings made from surveillance cameras there in the gymnasium where the body was found," attorney Chevene B. King Jr. told reporters in Valdosta, Georgia. 

"For some unknown reason, this tape has been withheld," he added. 

Gym mat death shocker: Body stuffed with newspaper 

Attorney Benjamin Crump, who recently joined the case after representing the family of slain Florida teenager Trayvon Martin, said that Johnson was "murdered, and we intend to get to the truth of what happened." 

Johnson was found dead at Lowndes County High School in Valdosta on January 11, his body resting headfirst in the rolled wrestling mat. 

A Georgia Bureau of Investigation autopsy found that he died from positional asphyxia, and the Lowndes County Sheriff's Office determined the death was accidental. 

But a second autopsy, which a private pathologist conducted at the request of Johnson's parents in June, found that he died because of "unexplained, apparent non-accidental, blunt force trauma." 

Teen's death not accidental, family's autopsy finds 

The Lowndes County sheriff has declared the case closed, and the U.S. Justice Department said in September that it wouldn't open a civil rights investigation. But Michael Moore, the U.S. attorney for the district that includes Valdosta, is reviewing the case and weighing whether to open his own investigation. 
How old is the deceased?
Male or female?
What was his name?
Where was he located?
Where in Georgia?
Where?
In what room?
How was he positioned?
In what?
On what date?
Who examined him after he died for the authorities?
What did they deem the cause of death?
Was it ruled a homicide?
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17
Attorneys for the family of a 17-year-old student found dead
Male
A Georgia Bureau of Investigation autopsy found that he died
Kendrick Johnson
Kendrick Johnson, they allege, was slain in January
Georgia
Attorneys for the family of a 17-year-old student found dead in a rolled-up gym mat at a southern Georgia high school
Valdosta.
Johnson was found dead at Lowndes County High School in Valdosta on January 11, his body resting headfirst in the rolled wrestling mat. 
Lowndes County High School
Johnson was found dead at Lowndes County High School in Valdosta 
in the gymnasium
"There is one eyewitness that we know is available -- it is the video recordings made from surveillance cameras there in the gymnasium where the body was found,
his body was resting headfirst
his body resting headfirst in the rolled wrestling mat. 

a rolled wrestling mat.
his body resting headfirst in the rolled wrestling mat. 
January 11
Johnson was found dead at Lowndes County High School in Valdosta on January 11,
Georgia Bureau of Investigation
A Georgia Bureau of Investigation 
from positional asphyxia
A Georgia Bureau of Investigation autopsy found that he died from positional asphyxia,
No
A Georgia Bureau of Investigation autopsy found that he died from positional asphyxia, and the Lowndes County Sheriff's Office determined the death was accidental. 

Lowndes County Sheriff's Office
nd the Lowndes County Sheriff's Office determined the death was accidental.