WASHINGTON — (CNN) There will be no charges filed in the 2013 death of Kendrick Johnson, the U.S. Justice Department said Monday, citing insufficient evidence in the Valdosta, Georgia, case.

A medical examiner determined in 2013 that Johnson died of “positional asphyxia” after he was found dead in a rolled-up gym mat at Lowndes High School.

Officials from the U.S. attorney’s office met with Johnson’s family Monday and informed them the investigation had concluded, the Justice Department said.

“The Department of Justice, in particular the lawyers and investigators who have worked tirelessly on this investigation, express their most sincere condolences to Kendrick Johnson’s parents, family, and friends,” Acting United States Attorney Carole Rendon said.

“We cannot imagine the pain of their loss, or the depths of their sorrow. We regret that we were unable to provide them with more definitive answers about Kendrick’s tragic death.”

Four months after Johnson’s body was found in a gym mat, the Georgia state medical examiner concluded he had died as the result of accidental “positional asphyxia,” implying Johnson had suffocated as a result of being trapped upside-down in the rolled-up mat.

The teen’s parents never believed the local authorities’ explanation that the 17-year-old teen got stuck in the mat after diving in to retrieve a shoe.

His parents, Kenneth and Jacquelyn Johnson, later had his body exhumed and hired a pathologist to performed a second autopsy on Johnson’s body.

In the second autopsy, two months later, a medical examiner concluded Johnson’s death was a result of a homicide.

Evidence of “blunt force trauma to the right side of Kendrick’s neck, near the jaw, and the manner of death was not an accident,” the Justice Department statement details. “He found hemorrhages to the jaw line area not detected during the GBI autopsy.”

In January, Johnson’s parents filed a $100 million civil lawsuit against dozens of local and state officials and claim officials helped plot to fake evidence.

Federal investigators hold firm that a comprehensive investigation was conducted surrounding the of the events in Kendrick’s death.

“The investigation included, among other things, interviewing nearly 100 people; reviewing tens of thousands of emails and text messages; reviewing surveillance videos from Lowndes High School; and analyzing other available information regarding the events of January 10-11, 2013,” the DOJ statement said.

The Justice Department said the investigation into this incident “has been closed without the filing of federal criminal charges.”