The U.S. Department of Justice is now investigating the shooting death of Trayvon Martin ... meaning, if slapped with federal charges, George Zimmerman could face jail time -- even after his not guilty verdict.
The DOJ issued a statement Sunday ... revealing they are looking into the case, evaluating the evidence (including testimony from the State trial) -- and will determine whether or not federal prosecutors should file criminal civil rights charges against Zimmerman.
Here's why it's important ... Zimmerman was found not guilty on Saturday of both second-degree murder and manslaughter when tried by the State of Florida -- and is technically a free man.
But since the news broke ... civil-rights activists have been up in arms, like Al Sharpton and the NAACP who are clamoring for the DOJ to bring civil rights charges against Zimmerman.
If the Feds decide to go through with new criminal charges ... then a jail sentence is back on the table.
Although, according to legal experts, it will be an uphill battle to prove in court that Zimmerman was motivated solely by race.