A serving police officer in Northern Ireland has been arrested over allegedly using Twitter to distribute sectarian, sexist and racist remarks.

The police ombudsman’s office in Belfast confirmed on Friday the officer was arrested by the policing watchdog.

The officer’s detention follows the police ombudsman, Dr Michael Maguire, initiating the investigation after receiving allegations this summer.

The ombudsman’s office is understood to be dealing with a number of complaints from members of the public in relation to the alleged misuse of Twitter. They include concerns over abusive messages and also the leaking of confidential material.

Last month the Guardian revealed that around half a dozen police officers and support staff were under investigation in Northern Ireland over allegations that they had posted racist, sexist and sectarian messages on Twitter and had potentially prejudiced criminal inquiries.

The group is also being investigated for allegedly tweeting pictures of bottles of urine from inside a police vehicle and showing their private parts beside guns.

The PSNI confirmed at the time that the police were looking into the claims that those behind the tweets were serving officers. They are under investigation from the PSNI’s professional standards department.

It is understood the six PSNI officers or civilian support staff under investigation are all based in the greater Belfast area.

The tweets include wholly unfounded fake rumours of a sex tape involving a Northern Irish journalist.

In another tweet, one of those alleged to have sent the messages brands the Catholic Lower Falls-Divis district of West Belfast as a place where “thieves operate ... like fucking rabbits”. Beneath the message is a map of the district with a red circle drawn around it.

Another post relating to the same district includes a photograph of a man alleged to have mugged a foreign tourist earlier this year.

Security sources in Northern Ireland said that this tweet was sent out before any arrest was made in connection with the crime. In tweeting the suspect’s face, those responsible were in danger of prejudicing any upcoming trial in connection with the mugging, the sources said.

There is also concern in security circles that those allegedly engaging with women online for sexual encounters could fall for “honey traps” set by armed republican dissident groups determined to kill PSNI members.

Some of those behind the messages even engage in Twitter exchanges with Saoradh – the new political party that supports prisoners belonging to the New IRA terror group.

The republican dissidents are taunted and told in one message that “my colleagues sit in on your meetings & private chats anyway. They fill me in.”

The tweet ends with the hashtag #C3, which is a reference to the PSNI’s anti-terrorist branch.

A security force veteran based in Northern Ireland, who brought the tweets to the attention of the Guardian, said those behind this particular message had openly admitted to the republican dissidents that they were being monitored via electronic surveillance.

Photographs of the interiors of heavily-fortified PSNI stations, including a CCTV monitoring station in Belfast, have also been tweeted in the stream being investigated. Other pictures of alleged crime suspects and convicted criminals sent include a message urging a prisoner to “put the rope up” and “hang yourself”.