The "tragic accident" occurred during a police firearms training exercise in Graz.
A police firearms instructor in Austria is under investigation after accidentally shooting dead a fellow officer during a training exercise.
Prosecutors in the southern city of Graz said the 39-year-old instructor had been handing practice weapons to the officers.
The instructor reportedly forgot that he was carrying his own service firearm, which was loaded in his holster.
During the training exercise, he tried to demonstrate that one officer was standing in a vulnerable position and fired on him at close range. The 27-year-old police officer was fatally wounded, prosecutors say.
A spokesperson for the prosecutor's office said there was no doubt that Wednesday's incident had been a "tragic accident."
The instructor is now being investigated on suspicion of grossly negligent homicide.