A Columbus man pleaded guilty to cyberstalking Delaware County Sheriff Russell Martin on Friday in U.S. District Court.

William E. Young, 54, appeared in U.S. District Court and entered a guilty plea to one count of cyberstalking, a federal crime punishable by up to five years in prison and a fine of up to $250,000. A sentencing hearing has not been scheduled yet.

Young was indicted by a federal grand jury in August and charged with cyberstalking Martin ever since Martin arrested Young for stalking a woman in 1999. Court documents indicate that Young created four web pages about Martin and allegedly mailed letters on numerous occasions to Martin’s wife and family, and to the Delaware Police Department, Delaware County Sheriff’s Office, Delaware County Jail, and numerous other local organizations and businesses.

According to court documents, Young confirmed the facts laid out by prosecutors and said he was guilty of the charge.

U.S. Magistrate Judge Norah McCann King presided at the hearing.

Young reached a plea agreement with federal prosecutors on Nov. 27 in U.S. District Court

Martin said on Twitter in November that he was “continually grateful for the diligence and competency” of the FBI and federal prosecutors. He added that he would release a statement after Young’s case is adjudicated.

After Young was indicted, Martin released a statement saying, “Over the last three decades in law enforcement, I’ve arrested or investigated thousands of criminals, many of them violent and extremely dangerous. The man the FBI arrested has threatened and harassed me and my family for years, and while I signed up for this job, my family didn’t. We deserve to be safeguarded from danger — just as any other citizen…”

Officials report that in a May 2010 interview with agents of the Ohio Bureau of Criminal Investigation, Young stated he wanted Martin fired and wanted him to “eat his gun.”

Federal officials also said that in September 2015, Young mailed a 62-page letter to Martin’s wife which included the following statement: “I’ll force his hand if the powers that be make the mistake of coming after me again. Then I’ll take everyone down who had a hand in what was done to me one by one.”

The case was investigated by the Cincinnati Division of the FBI.

Young remained in federal custody Friday.