The incident took place in September this year and led to a large police operation at the school in Falkenberg.
The verdict states that the police must have ordered the man to drop the knife, but that the situation then escalated.
The man is said to have moved at high speed towards the police, whereupon one of the policemen fired a warning shot.
The police must have wrestled the man to be able to arrest him.
He is now sentenced in Varberg District Court for unlawful threats, burglary and serious threats against an official to one year and nine months in prison.
The man himself has denied any wrongdoing.
This is how the operations manager told about the incident in September:
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Start the clip to see police chief Martin Svensson tell more about the incident and how he views the police's actions.
Photo: Marcus Alakangas / SVT