The select committee charged with investigating an August voting snafu on the House floor may call upon fewer lawmakers to testify than initially anticipated, opting instead to rely on videotapes and other records of the disputed vote.

Rep. Bill Delahunt (D-Mass.), chairman of the committee, said Friday that the panel soon will meet to determine which witnesses, including Members, will be asked to testify at public hearings expected to begin in April.

He declined to detail which lawmakers could be invited to the sessions — those likely to appear include Majority Leader Steny Hoyer (D-Md.), Minority Leader John Boehner (R-Ohio) and Rep. Mike McNulty (D-N.Y.), who was presiding over the chamber at the time of the incident. But Delahunt did say that videotape of the House floor, as well as other documents, could reduce the number of Members and aides needed to testify.

“That might eliminate the need for a number of witnesses,” Delahunt said.

In the meantime, the Massachusetts lawmaker said the committee is on schedule to complete its work before the August recess.

“We’ve made some progress and we’ve concluded a number of interviews, and I’m satisfied that we’re moving with all deliberate speed,” Delahunt said, praising his Republican colleagues, led by Rep. Mike Pence (Ind.). “We’ve worked well together.”

In recent weeks the panel has formally interviewed 17 House aides, including some in the House Parliamentarian’s and Clerk’s offices, and collected e-mail messages and other communications from relevant individuals.

A source close to the committee, who asked not to be identified, said the panel will convene this week to set a hearing schedule.

“We’ve reached a turning point and now we’re shifting to the public hearings,” the source said.

The investigation is focused on an Aug. 2 vote on a GOP-authored amendment to the Agriculture spending bill that would have prohibited illegal immigrants from accessing certain federally funded programs.

Republicans alleged that the Democratic majority mishandled the vote, resulting in the defeat of the measure. GOP leaders assert that a tied 214-214 vote — rending a defeat — announced by McNulty was inaccurate and that the motion had in fact passed 215-213 as Republicans changed their votes.

But Democrats dispute that version of events, noting that their own Members were changing votes on the House floor, resulting in the final tally of 212-216. McNulty later apologized for prematurely calling the vote.

The Select Committee to Investigate the Voting Irregularities of August 2, 2007, as the panel is formally called, is tasked with issuing a final report by Sept. 15. In addition to its investigation, the committee is charged with issuing recommendations to prevent similar incidents in the future.