The hunt is on for the mystery senator who, using a last-ditch maneuver, killed a bill expanding protections for government whistleblowers as Congress was on the verge of passing the legislation after a 12-year lobbying effort.

Just before lawmakers adjourned last month, the Senate passed the Whistleblower Protection Enhancement Act by a voice vote. After the bill cleared the House unanimously with some amendments, it returned to the Senate for a final vote — only for a single senator to put an anonymous hold on it. The hold was enough to scuttle the bill because there was not enough time to overcome the steep legislative obstacles to remove it before the end of the session.

Now the Government Accountability Project, or GAP, has teamed with WNYC’s On the Media radio program to “out” the bill-killer. “We’re asking our listeners to call, write, email their senators and ask them ‘did you kill this bill?’” says WNYC, which will post the answers on its website. “Hopefully we can blow the whistle on the senator that would refuse protections to government whistleblowers.”

The bill strengthens legal protections for federal workers who report fraud and abuse through legal channels. In an Op-Ed piece for the Los Angeles Times, GAP legal director Tom Devine raged that the single senator’s move “personifies how a tyranny of one threatens congressional accountability … Special interests know that all they need to find is one senator with flexible ethics to anonymously kill whatever bill they don’t like.”

As of Tuesday, GAP reports, “Seven senators (or their staffers) have come forward to explicitly deny being the culprit.”