Boston mayor Marty Walsh says he is disturbed by allegations that a Boston police officer posted offensive images online, allegations that are now the subject of an internal investigation by Boston Police.

In a statement to WGBH News, Walsh called the posts in question "very disturbing" and commended the Boston Police Department for launching a prompt investigation into allegations that they originated with a police officer.

On Friday, Boston Police Department Spokesman Sergeant John Boyd confirmed that an internal investigation is underway after BPD officials had received a complaint about images allegedly posted on Instagram by officer Carlson Breneus that contain mocking depictions of an older, apparently homeless man.

Boyd could not confirm whether the images, which have been circulating on Twitter, were originally posted by any member of the Boston Police Department.

A Twitter user named Frederick Joseph, of New York, posted what he said were screenshots of images from from Breneus’ Instagram account.

Boyd said that Breneus has been transferred from a specialized drug enforcement unit to a different post pending the outcome of the internal investigation. No Instagram account in his name is currently online, and Breneus has not responded to requests for comment on the investigation.