The dead officer has been identified as Clement Cockfield and his girlfriend, who is reportedly fighting for her life at the Georgetown Public Hospital is Shanice Fraser.
Based on information received, both parties were stationed at the La Grange, West Coast Demerara police station.
At around 20:00hrs, Fraser came off duty and Cockfield reported to work. The two who were said to be in a relationship, were involved in a conversation at the southern wing of the building when Fraser ran into the facility, covered in blood and screaming.
According to police, Cockfield reportedly chased her with his weapon and discharged several rounds at her before placing the gun to his head and pulling the trigger.
The 20-year-old was pronounced dead and Fraser was admitted to the GPHC for treatment. She is said to have been shot 5 times about her body.
Investigations are ongoing.