Updated: 12:39 a.m.

The storm surrounding beleaguered Rep. Anthony Weiner only intensified Wednesday, with key members of his own party distancing themselves from the New York Democrat and the prospects increasing for a costly ethics investigation that could require forensic analysis of his office communications and the deposition of staffers.

Weiner, in a lengthy and at times uncomfortable press conference on Monday, admitted to communicating and exchanging sexually explicit pictures with at least six women other than his wife, but he indicated he had no plans to resign. Although he might have hoped the press conference would tamp down the scandal, it has done anything but.

A host of Democrats are now calling for Weiner’s resignation, including Pennsylvania Rep. Allyson Schwartz, a leader at the Democratic Congressional Campaign Committee, Rep. Mike Michaud (Maine), Sen. Mark Pryor (Ark.) and ex-Virginia Gov. and former Democratic National Committee Chairman Tim Kaine.

“Having the respect of your constituents is fundamental for a Member of Congress. In light of Anthony Weiner’s offensive behavior online, he should resign,” Schwartz said in a statement.

Democrats were also ramping up pressure on Weiner behind the scenes, although leaders continued to pursue a soft-sell approach, hoping the New Yorker would leave office on his own accord. They fear he might dig in harder if he is subjected to more aggressive tactics.

DCCC Chairman Steve Israel (N.Y.) called Weiner on Wednesday to discuss the controversy, which has overtaken political discussions and essentially trampled the party’s Medicare messaging efforts.

According to informed sources, Israel did not push Weiner to resign or say he felt that was an appropriate step. Israel did use the conversation to express the growing frustration within the Caucus that Weiner’s scandal is not going away and has become an embarrassment and distraction for the party. A spokeswoman for Israel declined to comment on his conversation with Weiner.

Israel, Minority Leader Nancy Pelosi (Calif.) and Minority Whip Steny Hoyer (Md.) have called for an ethics investigation into the scandal. Other rank-and-file Democrats have stopped short of calling for Weiner’s resignation but signaled that he does not have their support.

Beyond the political concerns, the personal humiliation got worse for Weiner on Wednesday, as media outlets circulated an alleged photo of his genitalia and the New York Times reported that his wife is pregnant.

Meanwhile, ethics experts suggest Weiner and his staff could be facing a prolonged and expensive investigation by the Ethics Committee. Other Democrats are “likely to be encouraging and egging on the process rather than being a brake on it,” said Matthew Herrington of Steptoe & Johnson LLP.

The first step in any formal House Ethics Committee investigation would be a preliminary inquiry undertaken by Chairman Jo Bonner (R-Ala.) and ranking member Linda Sánchez (D-Calif.) to determine whether it is a matter serious enough to warrant the formation of an investigative subcommittee, which would then have the ability to discipline Weiner formally. Even if the inquiry does not progress to that stage, committee leaders could issue an informal report admonishing Weiner for his behavior, which could be politically damaging.

Herrington said even when an inquiry initially seems clear-cut, there is typically some “scope creep” once it begins.

“One of the things about an Ethics investigation is that once it starts, who knows where it leads,” Herrington said.

The Ethics Committee might begin by getting computer records from Weiner’s office and analyzing his email, Twitter and Facebook accounts, legal experts said. They would use that information to determine who will be called for questioning by the committee, either informally during a preliminary inquiry or subpoenaed during a formal investigation.

They can bring in “anybody that they think may have relevant information, and they can cast a wide net,” Zuckerman Spaeder’s Leslie Berger Kiernan said.

The legal fees incurred during a Congressional investigation can be steep.

So long as the scope of the inquiry relates to a Member’s duties in office — and an Ethics inquiry into Weiner’s communications would meet that criteria — the bills can be paid from money remaining in lawmakers’ campaign accounts.

As of the end of the first quarter, Weiner had approximately $365,000 left in his campaign war chest, according to CQ MoneyLine. But legal bills can quickly amount to hundreds of thousands of dollars, and it could be a challenge for Weiner to raise more money in the future.

When Rep. Peter Visclosky (D-Ind.) was investigated in 2009 for campaign donations he received from members of the PMA Group, the legal fees paid from his campaign account jumped to nearly $250,000 from just $7,000 the year before, CQ MoneyLine data shows. The House Ethics Committee ultimately cleared Visclosky of any wrongdoing.

There would also be legal costs for any Weiner staffers who may testify in the matter, though in many cases those are also paid from Members’ campaign accounts or a special legal defense fund.

“Legal expense trusts can be set up to benefit a Member, officer or employee of the House,” Kiernan said.

The longer the scandal continues to unfold, the less likely it is to go away, experts agreed. Even if Weiner resigns, an inquiry into the circumstances surrounding the illicit communications could go forward.

“His resignation would obviously end his being subject to disciplinary action by the committee, but if there’s some reason to believe there are institutional concerns, it could continue,” said Robert Walker of Wiley Rein LLP.

Alex Knott contributed to this report.

Editor’s Note:

This article updates the print version to include details on Democratic leaders’ response to the Weiner scandal.