Trandahl's lawyers said he is scheduled to testify Thursday before the House Ethics Committee, which is investigating the Foley case.

Two sources close to Trandahl told CNN that he had been monitoring Foley's interaction with pages after being told of troubling behavior by the congressman in the House cloakroom and elsewhere. Trandahl took his concerns to Kirk Fordham, Foley's former chief of staff, many times, the sources said.

Fordham testified last week that he warned House Speaker Dennis Hastert's chief of staff, Scott Palmer, at least three years ago about Foley's conduct, according to a source familiar with Fordham's version of events.

Palmer has denied Fordham's account.

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Trandahl, who was House clerk from 1998 to 2005, oversaw the page program and had day-to-day authority over the teens. Former colleagues describe him as a by-the-book manager who took his job seriously.

A friend, Craig Shniderman, told CNN that if Trandahl was aware of something improper, he would have reported it.

"Jeff is a guy who always does the right thing," Shniderman said. "He lives by the truth. He lives by one truth. He's not a man that tells different stories to different people."

Rep. Rodney Alexander, the congressman who warned House leaders about Foley's e-mails to a teenage boy from his district, testified before the Ethics Committee on Wednesday.

The Louisiana Republican said he wants to know who else knew about Foley's behavior.

Alexander spent about three hours testifying about Foley's contacts with teenage pages and how the chamber's Republican leadership handled concerns about Foley.

"We told them what we know, when we knew it, and what we did about it, and we are looking forward and hoping that the committee will talk to others," Alexander said. "It's quite apparent from some of the reports out there that there are many people that know what we know and have known it for a lot longer period of time than we've known."