Five police control room staff have been suspended amid claims they made hundreds of 999 calls to inflate performance figures.
The employees, hired by G4S Public Services, worked for Lincolnshire Police and are alleged to have made the test calls during quieter times to ensure they answered them quickly.
Emergency call handlers for the force are required to answer 92% of 999 calls within 10 seconds, or G4S Public Services is fined.
It is claimed the illegitimate calls were made in October, November and December 2015. Figures show 724 calls were made during this time.
The figures also showed the handlers missed their targets in November (90.19%), and December (89.24%). The bogus calls would have increased the figures to around 93%.
The Crown Prosecution Service have said the inquiry is an internal disciplinary matter, and there is no evidence of criminal activity at this stage.