Brian Hickerson was charged with one count of felony domestic violence on May 23 and pleaded not guilty

The felony domestic violence charge against Hayden Panettiere‘s ex-boyfriend Brian Hickerson has been dismissed, PEOPLE can confirm.

“The case against Brian Hickerson was dismissed without prejudice today,” a spokesperson for the Los Angeles County District Attorney’s Office told PEOPLE on Thursday. “Our office was unable to proceed because we could not secure a material witness. The protective order also was dismissed.”

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Hickerson’s lawyer did not respond to PEOPLE’s request for comment.

Panettiere and Hickerson began dating after reports circulated that she and then-fiancé Wladimir Klitschko had split in August 2018. Klitschko, 43, and Panettiere share daughter Kaya, 4, who lives in Ukraine with her father.

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While the relationship between Panettiere and Hickerson began as a fling, it was quickly questioned by those close to the Heroes alumna, especially after the former couple was reportedly involved in a drunken altercation with Hickerson’s father, prompting a visit from police. And in May, Hickerson was arrested on a domestic violence charge and released on bail.

According to the felony complaint obtained by PEOPLE, prosecutors had alleged Hickerson “willfully inflicted corporal injury resulting in a traumatic condition upon Hayden P.”

Hickerson was charged with one count of felony domestic violence on May 23 and pleaded not guilty, a spokesperson for the L.A. County District Attorney’s Office confirmed to PEOPLE at the time.

In July, according to RadarOnline, Hickerson appeared in court as a Los Angeles superior judge listened to the testimony from the police officer who responded to the domestic violence call on May 2. During the hearing, the judge denied the motion to dismiss criminal charges against Hickerson and declined to consider a lesser misdemeanor charge.