DOVER, Del. (AP) — State officials are trying to determine why court appearance notices were not mailed to thousands of criminal defendants in Delaware, some of whom may have been arrested for not showing up in court.

Technology workers are working to determine the cause and scope of the problem, which also resulted in some cases being dismissed for witnesses' failure to appear.

Officials said Friday that some 9,500 appearance notices for criminal cases in the Court of Common Pleas were not mailed between June 1 and Oct. 3. That's about 20 percent of all the notices the court meant to send out during that period.

Official steps to address the issue include withdrawing warrants in traffic arraignment and criminal cases in which notices to defendants were not sent.