According to the Post:
The committee concluded that Massa's resignation put him outside the reach of any punishment the committee could dole out, and would render any findings of wrongdoing irrelevant.
Because the committees' membership is evenly split between Democrats and Republicans, the decision to end the investigation would require all the Democratic votes plus at least one Republican vote, Attorney Stan Brand, a former House general counsel, tells TPMmuckraker.
The ethics committee, which announced March 4 it was investigating unspecified allegations against Massa, has not returned several calls for comment. Massa resigned on Monday.
Brand says that the committee did have the choice to continue its investigation, and that it even could have subpoenaed Massa, despite the fact that he is no longer in Congress.
"Having said that," Brand continued, "the committee most often in these cases doesn't continue because it has scarce resources and it has enough to do with sitting members."
There are exceptions.
They include the 2006 report on improper conduct involving House pages that focused on Rep. Mark Foley, who had resigned more than two months before the release of the report. Another example is the February ethics report on earmarking covering Rep. John Murtha, which was released a couple weeks after Murtha's death.