Facebook wants assurances from the US Drug Enforcement Administration that it's not operating any more fake profile pages as part of ongoing investigations.
Facebook's chief security officer, Joe Sullivan, said in a letter on Friday to DEA Administrator Michele Leonhart law enforcement agencies need to follow the same rules about being truthful on Facebook as civilian users.
Those rules include a ban on lying about who you are.
Sullivan's letter was in response to a New York woman's federal lawsuit claiming a DEA agent created a fake online persona using her name and photographs stored on her mobile phone.
In court filings, Sondra Arquiett said her pictures were retrieved from her mobile after she was arrested in July 2010 on drug charges and her mobile phone seized.
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Arquiett said the fake page was being used by DEA agent Timothy Sinnigen to interact with "dangerous individuals he was investigating". Arquiett is asking for $US250,000 ($A270,500) in damages.
"Facebook has long made clear that law enforcement authorities are subject to these policies," Sullivan wrote.
"We regard DEA's conduct to be a knowing and serious breach of Facebook's terms and policies."
Facebook also wants the DEA to confirm it has stopped using any other fake profile pages it may have created.
"The department has launched a review into the incident at issue in this case," Justice Department spokesman Brian Fallon said in response to a request for comment.
"That review is ongoing, but to our knowledge, this is not a widespread practice among our federal law enforcement agencies."
The Justice Department initially defended the practice, arguing in an August court filing that while Arquiett didn't directly authorise Sinnigen to create the fake account, she "implicitly consented by granting access to the information stored in her mobile and by consenting to the use of that information to aid in ... ongoing criminal investigations."
Last week the agency announced it would review whether the Facebook guise went too far.
The case was scheduled to go to trial this week but court records show it has been sent to mediation.
