LAWRENCEVILLE, Ga. -- Gwinnett County's solicitor-general has dismissed all cases involving two police officers who were fired after videos showed a controversial traffic stop.

Master Police Officer Robert McDonald, a 3-year veteran, was fired Thursday after a video captured by a witness showed him kicking a handcuffed man.

Sgt. Michael Bongiovanni, a 19-year veteran, was then fired when another video emerged showing him pull the suspect out of a car and punch him.

On Friday, Gwinnett County Solicitor-General Rosanna Szabo said cases in which the officers were the principal officers or a necessary witness were thrown out. That included 63 cases in Gwinnett County Recorder's Court and another 26 in Gwinnett County State Court.

The Solicitor's Office prosecutes misdemeanor cases and traffic offenses in Gwinnett County.

"When police officers betray the public’s trust and confidence, justice demands that all those cases that depend on their credibility be dismissed without delay," Szabo said in a news release.

Among the charges dropped include cases against Demetrius Hollins, the man punched and kicked on video.

Hollins had been charged with marijuana possession, obstruction and several offenses in connection with Wednesday's stop. In an incident last year, in which Bongiovanni was also an arresting officer, Hollins was charged with obstructing law enforcement, marijuana possession and a drug count.

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►AND | What we know about second fired Gwinnett County police officer

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A criminal investigation is underway into the actions of both fired officers. Gwinnett County District Attorney Danny Porter said the investigation is moving quickly.

"I would say that probably next week sometime we're going to meet with the police department and make some decisions," Porter said.

Possible charges against the two officers includes battery, assault under the color of law and violation of oath.