DNA tests have confirmed an autopsy ruling that the hanging death of Frederick Jermaine Carter was a suicide, says Leflore County Sheriff Ricky Banks.

Meanwhile, the Greenwood Commonwealth reports that national and local civil rights groups are pushing for a Justice Department investigation into the incident.

Carter’s body was found hanging from a tree Dec. 3.

Banks told the newspaper that his office sent the slip knot and the section of the rope that was tied around a branch to a private lab in Jackson for DNA testing. The lab found only Carter’s DNA on the rope, he said.

“To me that’s pretty conclusive that he put the rope around the limb,” said Banks. “If you are going to hang someone, you are going to throw the rope around the limb and tie the knot. He did that himself.”

The DNA results were consistent with a preliminary autopsy which ruled the death a suicide; Banks also has said the only footprints around the tree were Carter’s. Banks said the state Crime Lab found no traces of drugs, prescription or otherwise, in Carter’s system. Banks said he had the tests done to see if Carter was taking the medication prescribed for his schizophrenia.

Banks said family members have confirmed that Carter had been treated in 2008 for mental illness at the Mississippi State Hospital at Whitfield.

The NAACP is asking the Civil Rights and Criminal Divisions of the Justice Department to investigate under the federal hate-crime statute. Derrick Johnson, president of the Mississippi NAACP, said the civil rights organization wants “to ensure that there was no wrongdoing in this case.”

The NAACP’s statement claims there are “a series of inconsistencies” in the investigation conducted by local authorities. Johnson would not identify them.

“There have been a lot of questions that have been raised,” he said. “What those questions are, we will share with the Justice Department if it decides to intervene and do an investigation.”

Banks said he has concluded his investigation “unless something else comes up.” He said, though, that he had no objection to the NAACP’s call for federal authorities to conduct a separate investigation.

“I don’t have any problems with anyone they want to send. I don’t have any problems whatsoever. I don’t see the need for it.”