A top aide to the ex-US congressman who quit over an explicit e-mail scandal has testified before the House of Representatives ethics committee.
The row is dominating politics ahead of mid-term elections
The scandal was triggered by recent revelations that Mark Foley had sent lurid e-mails to young male staff.
Aide Kirk Fordham gave evidence behind closed doors. He was expected to say Republican leaders knew of Mr Foley's activity at least three years ago.
Mr Foley has said he is gay but denies any sexual contact with the teenagers.
Mr Foley resigned on 29 September after revelations that he had sent sexual messages to House pages - high school students appointed to help with administrative work.
The youngest recipient of the suggestive e-mails is said to have been 16 years old.
In his testimony, Mr Fordham was expected to say he warned House Speaker Dennis Hastert's chief-of-staff about Mr Foley's inappropriate conduct in 2003, or possibly a year earlier.
The chief-of-staff, Scott Palmer, has denied the claims.
Mr Hastert's aides say they only learned of an overly friendly e-mail in the autumn of 2005 and of sexually explicit ones last month.
Mr Hastert, who last week rejected calls for his resignation over his handling of the case, has said he will sack any member of his staff who may have covered up the e-mail scandal.
Jim Kolbe, the only openly gay Republican in Congress, said he became aware of Mr Foley's behaviour six years ago, after a young worker showed him inappropriate messages.
Mr Kolbe said he passed the information on "promptly" to the office that supervises the pages.
"I did not have a personal conversation with Mr Foley about the matter. I assume e-mail contacts ceased, since the former page never raised the issue again with my office."
The ethics committee, on which there are five Democrats and five Republicans, will examine who became aware of the allegations and when, although it has no jurisdiction over Mr Foley.
Committee chairman Doc Hastings said he hoped to finish the inquiry "in weeks", but it is unclear whether it will be complete before the 7 November mid-term elections.
The scandal is dominating US politics, with opinion polls suggesting it has already harmed President George W Bush's standing.