There’s about 3600 members of the Defend the Blue Facebook page, which The Australian reports was started a year ago by a senior police officer.

Carroll says the page was started with “good intentions” including support for mental health issues and “general chatter among mates”, but it has taken a dark turn in recent months.

Only serving and former Queensland police officers are allowed to join the the Facebook group, which has 3500 members, The Australian reports.

The page was created by a senior serving officer one year ago and has a number of posts criticising the Black Lives Matter movement and supporting Northern Territory Police Constable Zach Rolfe, who’s on trial for the alleged murder of Indigenous man Kumanjayi Walker.

Some of the controversial posts also criticise Premier Annastacia Palaszczuk and other state government MPs.

Ethical Standards Command is probing the page and those who made the controversial and in some cases “defamatory” posts.

The commissioner said Defend the Blue was difficult to investigate because it was a private page and some members were using fake names, but she expected preliminary action to be taken soon.

“I expect a professional organisation to serve their community. Well that site, its administrators, and some of the people on there, and the pseudonyms they use, will be investigated,” Carroll said.

“And if discipline action needs to be taken, it will be taken.”

Deputy Commissioner Steve Gollschewski said the force was disappointed “as an organisation” about the existence of the Facebook page.

He said any officers found to have done anything wrong would face the same consequences as any member of the public would.

“That matter is under investigation,” Gollschewski told reporters.

“But I’m happy to say here that we expect our police officers to be completely professional and appropriate at all times and anyone that has done the wrong thing can expect exactly what I say about the community: do the right thing, otherwise it’s consequences.”

It’s unclear whether the investigation’s findings or any disciplinary action taken against the group’s members will be made public as Queensland Police media has not responded to AAP’s queries about the probe.

Gollschewski wouldn’t comment on whether the page reflected a deeper cultural issue for the Queensland Police Service’s 12,000 officers.

“What it says is that like any organisation we have challenges with some of our employees from time to time, and we need to address them,” he said.