A police officer filmed seemingly punching a man in the head nine times is under criminal investigation.
The officer has been served with a gross misconduct notice after footage showed him with his arm around a man’s neck while appearing to hit his face in Porthmadog.
The Independent Office for Police Misconduct (IOPC) said the officer had been suspended by North Wales Police.
It said a second officer had also been served with a misconduct notice.
The second officer’s alleged conduct is related to the level of care given to the man after his arrest.
The IOPC said the first officer used an incapacitant spray on the arrested man as he was being put in the back of a police vehicle.
The incident happened after police were sent to a report of a disturbance at a property in the town in Gwynedd, north west Wales, at about 11:00 BST on 10 May.
The police watchdog said on the way to the police station the man appeared to become unwell and was given first aid.
He was then taken by ambulance to hospital and before being released back into police custody.
IOPC director David Ford said: “There has been considerable interest and public concern over the footage shared widely on social media, which shows some of the interaction between police officers and the man being arrested.
“We are progressing our investigation in a thorough and timely manner, carefully securing and examining a range of evidence to establish what took place during the whole incident.
He said that the misconduct notices “does not necessarily mean that criminal or disciplinary proceedings will follow”.