The incident occurred at a rest area 20 kilometres south of Miriam Vale in Colosseum about 10.50am.
Police said “investigations and subsequent responses are ongoing”.
Colosseum is a rural located in the Gladstone Region and has a population of about 218 people.
The Bruce Highway is closed at the site in both directions and diversions are in place.
Ethical Standards Command will investigate the incident with oversight by the Crime and Corruption Commission.
