A police officer filmed telling a suspect “chill out or I’ll choke you out” is under criminal investigation, a watchdog has said.

Footage of the arrest made by a West Yorkshire Police officer in Halifax on August 16 sparked outrage when it was shared widely on social media.

It showed two male uniformed officers grappling with Hassan Ahmed, 27, on the pavement.

One of the officers appears to say to him “chill out or I’ll choke you out” and then “chill out or you’re going to sleep”.

Around 100 people attended a protest outside Halifax police station in the days after the arrest, including Mr Ahmed’s sister Safyah, who said she was “sickened” by what had happened.

On Wednesday, watchdog the Independent Office for Police Conduct said the officer is under a criminal and gross misconduct investigation.

He had already been suspended.

IOPC regional director Miranda Biddle said: “Having examined a range of evidence, including body-worn video and initial accounts from the officers involved in the restraint, we have taken the decision that this is now a criminal investigation.

“A criminal investigation does not mean that criminal charges will necessarily follow.”