Los Angeles police were investigating after a Playboy model took a photo of a naked woman in a gym locker room and posted it to social media with insulting comments about the woman's body, authorities said.

Dani Mathers faced widespread criticism after she shared the photo on Snapchat with the caption: "If I can't unsee this then you can't either." She later apologized, saying the post was meant to be a private message, and deleted her social media accounts.

A new Twitter account appeared that "is run by a community manager of Dani."

Sorry to everyone. I apologize for this stupid picture. Thank you for your support <a href="https://twitter.com/hashtag/snapchat?src=hash">#snapchat</a> <a href="https://twitter.com/Playboy">@Playboy</a> —@DxMathers

Detectives were investigating after the LAPD received a report of "illegal distribution" of the image, police Capt. Andrew Neiman told the Los Angeles Times on Sunday.

The gym, LA Fitness, reported the posting to police and has revoked Mathers' membership.

"Her behaviour is appalling and puts every member at risk of losing their privacy," said Jill Greuling, the company's executive vice-president of operations.

The company would not say at which gym the incident occurred. The woman in the photo was not identified and it was not clear if she knew she was being photographed.

Mathers said she accidentally posted the photo publicly.

"That was absolutely wrong and not what I meant to do," she said in an online video. "I know that body-shaming is wrong. That is not the type of person I am."

Mathers, 29, was Playboy's Miss May in 2014.