WASHINGTON — The House speaker, Rep. Dennis Hastert, testified in private before ethics investigators yesterday and then said they should work quickly to find out who knew about Rep. Mark Foley’s come-ons to congressional pages and what was done about it.

Mr. Hastert spoke briefly after his closed-door testimony to the House ethics committee that is trying to pin down when he and his staff learned about Mr. Foley’s actions.

“I answered all the questions they asked to the best of my ability,” Mr. Hastert said after testifying for almost three hours. “I also said that they need to move quickly to get to the bottom of this issue, including who knew about the sexually explicit messages and when they knew about it.”

Mr. Hastert has denied any Republican knew of the messages from Mr. Foley to former pages. His office has described only how Republicans handled an incident last fall involving “over friendly” e-mails to a former page from Louisiana. The timeline that Mr. Hastert and his staff have given conflicts with the accounts of others. Mr. Hastert, a Republican of Illinois, said he didn’t find out about Mr. Foley until late September, when Mr. Foley’s approaches to the former pages became public and the Florida Republican resigned his seat.

Mr. Hastert’s appearance followed that of Rep. Tom Reynolds of New York, the House GOP campaign chairman, who said he warned the speaker about Mr. Foley last spring.

Mr. Hastert has said he didn’t recall that conversation. He also has been unable to recall whether he spoke with Majority Leader John Boehner about Mr. Foley last spring, although Mr. Boehner says Mr. Hastert even told him the matter was being handled.

There is a separate conflict over whether Mr. Hastert’s top aides learned about Mr. Foley a year ago, as the speaker says, or whether the speaker’s chief of staff was told as much as three years ago — as asserted by Mr. Foley’s one-time chief of staff.

The speaker has vowed to fire any of his aides if they covered up knowledge of Mr. Foley’s behavior.