A grand jury in the US capital has issued indictments for 19 people, including 15 identified as Turkish security officials, for attacking protesters in May 2017.
The indictments, announced on Tuesday, charge the defendants with attacking peaceful demonstrators who were protesting against the visit of Turkish President Recep Tayyip Erdogan on May 17.
All 19 are charged with conspiracy to commit a crime of violence, a felony punishable by a statutory maximum of 15 years in prison. Several face additional charges of assault with a deadly weapon.
Sixteen of the defendants had already been charged on June 13; Tuesday's indictment adds three new defendants, all Turkish security officials.
All but two of the 19 remain at large. Two Turkish-American businessmen were arrested in June for their roles in the daylight attack on protestors and face an initial court hearing on September 7.
Of the other 17, two are Canadians, and the rest are Turkish nationals.
Video of the protest showed security guards and some Erdogan supporters attacking a small group of protesters with their fists and feet.
Men in dark suits and others were recorded repeatedly kicking one woman as she lay curled on a sidewalk. Another wrenched a woman's neck and threw her to the ground. A man with a bullhorn was repeatedly kicked in the face.
After police officers struggled to protect the protesters and ordered the men in suits to retreat, several of the men dodged the officers and ran into the park to continue the attacks. In all, nine people were hurt.
On the day of the violence, police detained two members of Erdogan's security detail but released them shortly afterward. Two other men were arrested at the scene - one for aggravated assault and the other for assaulting a police officer.
American officials strongly criticised Turkey's government and Erdogan's security forces for the violence; the State Department summoned Turkey's US ambassador to complain. The Turkish Foreign Ministry then summoned America's ambassador to protest the treatment of the detained security guards.
Turkey's official Anadolu news agency said at the time that Erdogan's security team moved in to disperse the protesters because "police did not heed to Turkish demands to intervene".
The Turkish Embassy claimed the demonstrators were "aggressively provoking Turkish-American citizens who had peacefully assembled to greet the president. The Turkish-Americans responded in self-defence and one of them was seriously injured."
In June, Erdogan also hit back at the allegations, accusing US police of having allowed "terrorists" to protest "50 metres from me" during his US visit.
Erdogan claimed Kurdish PKK fighters and members of what Turkey calls the Fetullah Terrorist Organisation (FETO) were united in protest against him.
"Why would I bring my guards with me to the United States, if not to protect me?" he said in a speech in Ankara, adding that he will fight the charges "politically and judicially".
Rex Tillerson, US secretary of state, said in June that the charges "send a clear message that the United States does not tolerate individuals who use intimidation and violence to stifle freedom of speech and legitimate political expression".