Three people were taken to hospital following a head-on crash near Deiniolen.
A man was seriously injured in the two-vehicle collision on the A4244 at just before 4pm last Friday afternoon.
The crash, involving a Chevrolet Matiz and a Ford Transit, occurred between the Ty Mawr tearooms and Beran Gerage.
The Chevrolet driver and his female passenger were both taken to Ysbyty Gwynedd in Bangor, before the man was transferred to a specialist unit at the Royal Stoke University Hospital.
The Chevrolet passenger sustained only minor injuries and was later discharged from Ysbyty Gwynedd. The driver of the Ford Transit also suffered minor injuries.
PC Daniel Owen from North Wales Police said: "The investigation to establish the cause of the collision is underway and I am appealing to anybody who may have witnessed the collision, or who may have been travelling in the area around the time of the collision and who may have dash cam footage, to contact us immediately."
Anyone with information should contact the Roads Crime Unit at North Wales Police via the live web chat or by calling 101, quoting reference no. 25000528948.
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