MONROE, N.C. - Health department officials are investigating more than a dozen illnesses linked to a Union County doughnut shop.

County health officials say an anonymous caller earlier this month reported that many employees of a Dunkin' Donuts shop were sick with a gastrointestinal illness.

Officials followed up and found out that six employees were sick. Six relatives of employees were also ill with a stomach bug.

Tests are being done to determine what causes the illnesses, and the business is still open. No customers have reported getting sick.