George Zimmerman, the man who was acquitted of murder in the shooting death of Trayvon Martin, has received a criminal summons for stalking, the Seminole County Sheriff’s Office said in a press release on Monday.

Zimmerman is accused of repeatedly threatening and harassing Dennis Warren between December 16 and December 25 of last year, the sheriff’s office said.

Warren is a private investigator who was hired by a production company that was working on a documentary about Martin’s life, according to CNN affiliate WKMG. Deputies said Zimmerman called Warren 55 times, left 36 voicemails, texted him 67 times and sent 27 emails over a nine-day span, WKMG reports.

The findings of that investigation were delivered to the sheriff’s office on March 14, and a summons and a notice of information was issued for Zimmerman. He was personally served on May 3, and his arraignment is scheduled for May 30, according to the press release.

The criminal charge adds to a lengthy list of legal issues for Zimmerman. He was a neighborhood watch captain in Sanford, Florida in February 2012 when he shot and killed Martin, an unarmed black 17-year-old.

In 911 calls from that night, Zimmerman told a dispatcher about a “real suspicious guy” walking in the neighborhood. The dispatcher asked Zimmerman if he was following the person, and he responded “yes.”

“OK. We don’t need you to do that,” the dispatcher responded. Still, Zimmerman continued to follow him, leading to the fatal shooting.

Zimmerman claimed he was acting in self-defense when he shot Martin. After a public outcry, he was charged in April 2012 with second-degree murder. A jury found him not guilty in July 2013.

Later, Zimmerman was arrested on suspicion of aggravated assault and domestic violence with a weapon in January 2015. Prosecutors decided not to file charges in the case after the alleged victim backed off her claims.

He also drew outrage when he attempted to auction off the gun that he purportedly used to kill Martin.