The shooting occured in July last year when a young man went on an unprovoked knife attack against civilians in the centre of the normally peaceful seaside town of Varberg.
The man went on a rampage, stabbing two men and one elderly woman who later died of her injuries.
The 24-year-old approached police who arrived on the scene with the 34-centimetre kitchen knife in hand, challenging officers to shoot him. The officer fired two warning shots that were ignored, then one at the man's leg that missed, the charge sheet read.
He then fired a successful shot at the knife-wielding man's other leg, but when he continued to crawl towards the officer, he was shot in the abdomen. The gun shot victim died in hospital later the same day from his injuries.
Charges were filed on Wednesday against the officer for manslaughter or professional misconduct. The prosecutor said that it was not justified to fire the last shot, as the man was already gravely injured from the thigh wound and posed no immediate threat to the police officer.
Friends of the deceased 24-year-old had warned local police previously over his deteriorating state of mind.