An assistant chief constable has been arrested and suspended but his force has refused to say why.

Cleveland Police Assistant Chief Constable Adrian Roberts has been released while an investigation is carried out into allegations which have not been made public.

The case has been referred to the Independent Office of Police Conduct.

Cleveland Police says he has been suspended on suspicion of gross misconduct but added that the suspension was a "neutral act".

It would not say why ACC Roberts was arrested and urged the media not to speculate.

A spokesman said: "A decision has been taken to suspend a senior officer on suspicion of gross misconduct.

"There is a presumption of innocence throughout any investigative process, which is right, fair and proper, and we would ask in the interests of fairness that the media do not indulge in speculation.

"Suspension is a neutral act and it is important for all those concerned and the integrity of the investigation that the individual concerned is innocent unless demonstrated otherwise.

"The matter has been referred into the IOPC.

"We can confirm that the officer concerned has been arrested and released under investigation."

Asked why the reason for his arrest has not been released, the spokesman replied that, in line with the College of Policing's Authorised Professional Practice, the arrested man's identity was not being released.

But the spokesman added that, as a name has been published by the media, "we do not intend to give further details of the investigation, conduct or arrest".

The IOPC said it has returned Cleveland Police's referral of the matter back to the force as the alleged conduct happened outside of England and Wales and therefore out of the watchdog's jurisdiction.

A spokesman said: "We have informed Cleveland Police of our decision and asked that if any conduct matters come to light that fall within our remit, they should refer them for our immediate consideration."

Cleveland Police Chief Constable Mike Veale resigned in January less than a year into his role. 

In September last year Police Oracle reported that then CC Veale had a case to answer for misconduct for allegedly lying about how his work phone was damaged. Chief Constable Richard Lewis tooks charge of Cleveland this month becoming the force's sixth chief in six years.