According to a report by Wall Street Journal, prosecutors asked judges to drop charges against four guards in November. Then they dropped charges against seven others on February 14, the day before State of Secretary Rex Tillerson’s visit to Turkey.

A source told WSJ that Tillerson, in his private talks with Turkish leaders, pointed to the decisions to drop charges—which hadn’t been publicized or announced—as an example of how the U.S. had addressed Mr. Erdogan’s grievances.

Erdogan’s guards attacked peaceful protestors in front of the Turkish embassy after receiving orders from Erdogan himself.

Videos of the incident show the guards punching and kicking protestors. Nine of them were hospitalized.

The attack was described as an unprovoked and “brutal attack on peaceful protesters” by District of Columbia Police Chief Peter Newsham.

The prosecutors are pursuing assault charges against four other members of Mr. Erdogan’s security team, as well as two Canadian citizens, none of whom have been arrested.

Two American citizens are awaiting sentencing after they pleaded guilty in December to felony assault charges for their roles in the incident.