Reports: U.S. investigating if service member staged an insider attack in Syria

Flashback: An attack at a small base in northern Syria in April left four service members with "possible traumatic brain injuries" and other minor wounds, per the Washington Post.

• U.S. officials originally said the attack was caused by indirect fire on the base. But the military later released a statement saying the attack was a “deliberate placement of explosive charges by an unidentified individual(s) at an ammunition holding area and shower facility.”
• Officials said the attack happened in the middle of the night, which suggests the perpetrator did not try to cause mass casualties, CNN reports.
• But the timing suggests the suspect may have tried to escape quietly or quickly, officials told CNN.

What's next: The Army's Criminal Investigation Division and the Air Force Office of Special Investigations are conducting the investigation into the attack, per CNN.

• "The investigation is ongoing, which may or may not, develop sufficient evidence to identify a perpetrator(s) and have enough evidence to ensure a conviction in a court of law," the Pentagon said in a statement to CNN. "No further information will be released at this time."

U.S. Central Command and the Department of Defense did not immediately respond to Axios' request for comment.