All three released statements denying any wrongdoing.
The OCE doesn't comment on investigations. But, as the New York Times reports, its letters notifying the other five members of its dismissals show that the office was looking into timing that may have given the appearance of special treatment or bought votes.
From one OCE document dismissing the case against Rep. Jeb Hensarling:
If Representative Hensarling solicited or accepted contributions in a manner which gave the appearance that special treatment or access was being provided to donors or the appearance that the contributions were linked to an official act, then he may have violated House Rules and Standards of Conduct.
Rep. Frank Lucas (R-OK), one of the members whose case was dismissed, wrote a letter to the OCE expressing relief but excoriating their methods.
"The lack of confidentiality has led to all eight members involved in this inquiry having our reputations irreparably damaged by the viral press coverage. While it is clearly too late for me, I would encourage the OCE to conduct interviews with the Member prior to making an outside document request. I believe that nothing is gained by punishing Members in the press before you review our office policies and documents," he said.
The fact that the OCE had been investigating several members has been in the news since June, when the OCE requested documents from several lobbyists.