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SENECA, S.C. — No criminal charges will be filed against a South Carolina police officer who fatally shot a 19-year-old during a drug sting, a state prosecutor announced Tuesday.

Solicitor Chrissy Adams said that after reviewing the case, she has determined Seneca officer Mark Tiller won't face state charges. The U.S. Department of Justice also is investigating, and Adams said she won't release additional information while those federal authorities decide whether they'll bring charges against Tiller.

The family of the 19-year-old, Zachary Hammond, wanted Adams removed from the case because she works closely with local police, but the state Supreme Court rejected the request.

Related: Lawyer Calls Zachary Hammond Shooting 'Ridiculous'

Adams said she announced her decision after meeting Tuesday with members of the Hammond family. The family attorney did not immediately return a message from The Associated Press seeking comment.

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Zachary Hammond. Courtesy of Eric Bland

Greg Dietterick, the city administrator for Seneca, said in a statement that "we are thankful the investigation has come to an end and shows Lt. Tiller was acting in self-defense. It is now time to start healing Seneca," a community of about 8,200 in upstate South Carolina, a few miles west of Clemson.

John Mussetto, a Greenville, South Carolina, attorney who represents the officer, said he had no comment.

Hammond was killed July 26. He had just taken a woman on a first date, during which they got ice cream at McDonald's, then drove to Hardee's so Hammond could get a hamburger, according to a federal lawsuit filed by his family.

Seneca police said they were waiting at the Hardee's after an undercover officer arranged a drug deal with the woman, Tori Morton. As officers pulled up to Hammond's car with lights flashing, he accelerated to leave, authorities said.

Related: Parents of Zachary Hammond, South Carolina Teen Killed by Cop: 'We Just Want Answers'

The woman was not injured and later was charged with simple possession of marijuana

Tiller has said through his lawyer that he thought Hammond was threatening to run him over and fired twice to protect himself. Hammond's family said a private autopsy showed the teen was shot in the side and the back, proving the threat had passed.

City lawyers have said the shooting was justified and that Tiller shot Hammond in self-defense.

Hammond's family says Tiller threatened to blow Hammond's head off. The officer's attorneys deny that.

Lawyer Eric Bland has said the family talked to the woman in the car, looked at private surveillance camera footage and did the private autopsy.

The family's lawsuit says that after paramedics determined Hammond was dead, his body was left for 90 minutes on the ground, where it was bitten and stung by ants. A second officer gave the lifeless teen's body a high-five sometime after other investigators arrived, according to the lawsuit.

In legal papers, lawyers have acknowledged that the second officer may have said something about inappropriate contact with Hammond's body.