A former custody sergeant was cleared of assault after an incident in which a man was left with two broken teeth.
An investigation was launched into the events that took place in the custody suite at St Anne Street police station, in Liverpool, on December 16, 2018.
It was alleged that former Sgt Peter Jordan used excessive force on the man, who had been arrested for drunk and disorderly behaviour, when bringing his head down onto the booking-in desk.
The investigation also looked at the language used by ex-Sgt Jordan, who has since left the force, towards the man while he was at the custody desk.
A complaint was later received from the victim, and the IOPC (Independent Office for Police Conduct) also received a mandatory referral from the force.
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After interviewing former Sgt Jordan and other witnesses, as well as reviewing CCTV footage, the IOPC found ex-Sgt Jordan had a case to answer for gross misconduct. This finding was accepted by Merseyside Police.
The matter was also referred the matter to the CPS (Crown Prosecution Service), who authorised a charge of assault occasioning actual bodily harm.
After a trial, the ex-Merseyside Police officer was cleared of ABH.
IOPC Regional Director Amanda Rowe said: "Following a detailed investigation, we found an indication that a criminal offence may have been committed and that the case should be referred to the CPS.
"It is important for police officers to be accountable for their actions so it was right that the matter should be given a fair hearing in open court and we thank all those involved in this process.
"In light of the jury's verdict that a criminal offence was not committed, we will now consider what further action, if any, should follow."
