Tayside Division police have been criticised in a damning report into how an Angus accident was handled.
The Police Investigations and Review Committee (PIRC) found officers could have prevented a crash caused by a drink-driver if earlier intelligence had been acted on.
Four people were injured on June 30 when the 19-year-old driver lost control of his vehicle on a road near Forfar, collided with a wall and sustained serious head injuries.
Three male passengers in the black Peugeot 206 also sustained injuries, one of them serious.
Shawn Kenny was later arrested and convicted of driving under the influence of drink or drugs, and the officers involved were referred to the complaints watchdog.
Commissioner John McNeill found police had failed to act appropriately after being told Kenny was driving under the influence.
Professor McNeill said: “Officers of Police Scotland, Tayside Division failed to respond appropriately and effectively to information provided about a person driving whilst his ability to do so was potentially affected by alcohol.
“Had additional information been obtained and circulated appropriately to other operational officers there was potential to stop and breathalyse the person thereby preventing a later serious road accident in which four members of the public were injured, two seriously.”
The investigation was the third to be launched in a month over incidents in Angus.
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