WASHINGTON — The lawmaker who exchanged sexually explicit instant messages with a House page is the same who worked with Sen. Orrin Hatch, R-Utah, on a recently approved law specifically aimed at protecting children.

Former Rep. Mark Foley, a Republican representing Florida, resigned Friday after media reports exposed he had inappropriate e-mail and instant messaging exchanges with former House pages — high school students younger than 18 years old who work in the House or Senate. Monday, it was announced that Foley has entered a rehabilitation program for alcoholism and behavioral problems.

Foley was head of the Congressional Missing and Exploited Children's Caucus and appeared with Hatch at the White House bill-signing ceremony in July approving the Adam Walsh Child Protection and Safety Act of 2006.

"This was shattering news," Hatch said. "It's really unsettling to me that someone who worked so hard to pass what everyone is saying is a landmark child protection law could do something like this. I just don't understand it."

Foley, 52, sent e-mails to a former page of Rep. Rodney Alexander, R-La., in the fall of 2005 asking the boy to send him a photo of himself. A series of instant messages released by ABC News have Foley, under the screen name Maf54, corresponding in 2003 with another former page asking him what he is wearing and sexually explicit questions.

The last message made public by ABC News has the minor saying "well i better go finish my hw (homework) ... i just found out from a friend that i have to finish reading and notating a book for AP English."

None of the pages involved have been identified but all are said to be younger than 18 when the contact took place.

"I'm deeply aware of the trust parents place in the Congress when they send their children to serve here as pages, or as interns for that matter," Hatch said. "I worry about the young people involved, and their parents. There has to be serious consequences for anyone who violates that trust, so things like this don't happen again."

The newly signed law Foley supported set up the Internet Crimes Against Children Task Force that provided funding and training to state and local law enforcement to work on sexual exploitation of minors over the Internet.

"It's not a coincidence, it's a cover-up," said Rep. Chris Cannon, R-Utah, of Foley's involvement with the bill. Cannon knew Foley "quite well" but found the six-term Florida congressman "irritating," particularly in some of his mannerisms.

"You don't need 'gaydar' to understand he has certain dispositions," Cannon said.