WASHINGTON - The mother of slain University of North Dakota student Dru Sjodin said Thursday it was "very, very surreal" to attend a White House bill-signing ceremony for a new law to protect against child predators.

Linda Walker joined "America's Most Wanted" host John Walsh and other families of victims at a ceremony when President Bush signed a law that requires convicted child molesters to be listed on a national Internet database and face a felony charge for failing to update their whereabouts. The database will be named after Sjodin.

Outside the White House, Walker had tears in her eyes as she hugged Sen. Byron Dorgan and Rep. Earl Pomeroy, D-N.D., sponsors of "Dru's Law" in the House and Senate.

"I'm not sure I could wrap my head around it all," Walker said.

Sjodin, 22, of Pequot Lakes, Minn., disappeared from a Grand Forks, N.D., shopping mall in November 2003. Her body was found the following April in a ravine near Crookston, Minn.

A convicted sex offender, Alfonso Rodriguez Jr., of Crookston, is charged in federal court with kidnapping resulting in Sjodin's death. He is currently standing trial in Fargo, N.D. Prosecutors say they will seek the death penalty if he is convicted.

Walker has spent much of the last two years traveling to Washington in support of the offender's database, lobbying members and studying the details of the many bills that have included parts of "Dru's Law."

"I was thrust back into Government 101," Walker said.

The bill that was signed Thursday had stalled for a long time, but eventually moved out of House-Senate negotiations as part of a larger measure to curb child predators.

"She was an advocate like none other I have experienced," Pomeroy said of Walker. "She was persistent, and she knew the issues inside and out."

Walker said after the ceremony that the day was rather bittersweet for her.

"I knew I wasn't going to give up until it was done," she said, adding that she doesn't think her work protecting children is finished.

The measure aims to help police find more than 100,000 sex offenders by creating the first national online listing available to the public and searchable by ZIP code. It also calls for harsh federal punishment for sexually assaulting children, including the possibility of the death penalty when a victim is murdered.

At the ceremony, Bush said the new law will help prevent child abuse by creating the national child abuse registry and requiring investigators to do background checks on adoptive and foster parents before they are approved to take custody of a child. Giving child protective services professionals in all 50 states access to this information will improve their ability to investigate their child abuse cases, he said.

Child advocates have called the bill the most sweeping sex offender legislation to target pedophiles in years. It would:

3 Establish a comprehensive federal DNA database of material collected from convicted molesters, and procedures for the routine DNA collection and comparison to the database when someone has been convicted of such an offense.

3 Provide federal funding for states to track pedophiles using global positioning devices.

3 Allow victims of child abuse to sue their molesters.

The law imposes a mandatory minimum sentence of 30 years for raping a child; a mandatory 10-year penalty for sex trafficking offenses involving children and for coercing child prostitution; and increases minimum sentences for molesters who travel between states.

The larger measure is named after Walsh's 6-year-old son, Adam, who was abducted exactly 25 years ago Thursday, and subsequently murdered.

"This bill is going to save the lives of children," said Dorgan after the ceremony.

Walker's friend of 20 years, Liz Nelson, accompanied her to the event.

"It was overwhelming, exuberant, bittersweet," Nelson said. "It was really a beautiful moment for all of us. I believe (Dru) is here with us in spirit and she's throwing her hat up for her mom and her family."