The incident took place in Hartford County around 1:30 p.m., Tuesday, Dec. 28, in Bristol.
Police officers responded to a large parking lot located at 100 North Main St. that was being used to complete on-site COVID-19 tests.
According to Lt. Geoffrey Lund, of the Bristol Police, an unidentified female called the main office of the company administering the tests and was upset about the service and time she was waiting in line.
The unidentified female threatened to shoot people at the Bristol site, Lund said.
After Bristol officers ensured the scene was safe, a decision was made by the company to terminate testing for the day, he added.
Officers remained on scene to ensure an orderly and safe disbursement of all vehicles on scene.
The company and Bristol police coordinated together to re-open the site on Wednesday, Dec. 29, Lund said.
Two officers are on scene and no other issues have arisen.
The threat made by the unknown female continues to be investigated by the detective division.
There is a high demand for COVID-19 tests, and people attending these sites are asked to exercise patience and civility, Lund added.
Anyone with information concerning the threat is asked to contact the Bristol police department at (860) 584-3011.
Click here to follow Daily Voice Norwich and receive free news updates.