The law in question is called the Biometric Information Privacy Act. It gives consumers the right to sue if a company uses biological identifiers, such as fingerprints or “faceprints” (the distinct shape of a face), without permission.

In the last year, the law has become a thorn-in-the-side of Facebook (FB) and Google (GOOG), embroiling them in lawsuits over their photo “tagging” tools that identify people by scanning their faces.

Last week, for instance, Facebook suffered a major defeat when a judge rejected the company’s attempt to throw out a class action suit based on the Illinois law.

In response, the tech companies are trying to ditch those lawsuits by amending the law, according to Chris Dore, who is the lawyer leading the Facebook class action.

Dore points to a draft bill, led by state Senator Terry Link (D), that rewrites the definitions of “photograph” and “scan.” Under the new definitions, Google and Facebook appear to be shielded from liability related to face-scanning.

A public interest group, the Center for Democracy & Technology, on Friday criticized the bill, describing it as an “unnecessary loss of privacy.”

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In a phone interview, Dore said the process is taking place “under cover of darkness,” but said he only has circumstantial evidence that Facebook and Google are behind the amendment. He claims, for instance, that Facebook has retained a Chicago law firm, Freeborn and Peters, known for its lobbying work.

In response to email inquiries from Fortune, Facebook would not confirm or deny it has been involved in the drafting of a bill. Earlier on Friday, the company stated, “We appreciate Sen. Link’s effort to clarify the scope of the law he authored.”

Google did not respond to a request for comment about the law.

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It’s unclear for now if the amendment will pass. Dore fears that Illinois lawmakers are rushing to pass it over the weekend, before the legislature adjourns for recess on Tuesday.

In a phone call, a staff member from Senator Link’s office said the Link has put the bill on hold, but could not clarify for how long, nor predict if the bill would pass by Tuesday. We’ll update if we hear anything further. Update: on Tuesday, Dore said the amendment has yet to move forward – meaning there will be no change to the law in the immediate future.

The legal fight in Illinois comes at a time of mounting public concern over how companies are using facial recognition technology. In Russia for instance, smart phone owners can use a popular app to scan the face of strangers and identify them on social media. Meanwhile, governments in Europe and Canada have curtailed how tech companies can use the technology.