Trooper Larry Lovick resigned from the patrol in June amidst an investigation into sexual misconduct allegations.
According to documents obtained by ABC11, the incident took place during a traffic stop on May 24.
The State Bureau of Investigation has now finished its probe of the matter and turned its findings over to Willoughby. He did not say when he would make a decision on the case.
Lovick was assigned to Highway Patrol Troop C, District 3.
His case was another in a long line of troopers being investigated recently for everything from inappropriate sex, to K-9 abuse, to drunk driving, and deadly accidents.
Highway Patrol commander Colonel Randy Glover stepped down from his post earlier this year and Governor Beverly Perdue named a panel to investigate problems within the department.
New commander Colonel Michael W. Gilchrist took over at the end of October.