Walsh, host of Fox's "America's Most Wanted: America Fights Back," said he and Lunsford have talked by telephone about the trial of John Couey, which is under way in Miami.

Couey is accused of taking 9-year-old Jessica from her Homosassa home, sexually assaulting her and then burying her alive.

"Mark said he was afraid the trial would bring back bad memories," Walsh said in a telephone interview Tuesday.

"I told him that he had already been through the worst: He had lost a child. I told him to be strong and keep doing what he is doing in Jessica's name."

Lunsford has said that he planned to sit through the whole trial, but Walsh begged him not to be there when any crime scene or autopsy photographs are introduced.

Walsh praised Lunsford's effort to get the Jessica Lunsford Act passed in Florida. The law provides a minimum of 25 years in prison for those who prey on children younger than 12, and if they are released from prison, lifetime tracking by a global positioning satellite.

Walsh, who has homes in South Florida and Washington, D.C., was in Broward County this week taping a segment for his TV series, which is in its 20th year.

This week's episode (9 p.m. Saturday) will focus on sexual predators. It also will include a report on seven Medals of Honor that were stolen recently from a Charleston, S.C., museum.

"Catching predators has special meaning for me because of Adam," Walsh said.

Adam was 6 when he was abducted from a mall in Hollywood, Fla. His killer was never caught, but Walsh and his wife, Reve, believe that a convicted serial killer, Ottis Toole, murdered their son. Toole died in prison in 1996.

Walsh said he does not believe that infamous serial killer Jeffrey Dahmer, who also died in prison, killed Adam. This theory has been investigated before and discounted, he said.

Walsh dismissed a new book by a Miami author of true crime stories that claims Dahmer is the most likely suspect. Walsh said the author was "bending the facts" to sell a book.

"There is no closure for the parents of a murdered child, but we hope for justice for Adam one day," Walsh said.

He said he gets some justice every time criminals are captured after being profiled on "America's Most Wanted." Since the series began, more than 900 fugitives have been apprehended.

Walsh applauded NBC's "Dateline: To Catch a Predator" series for calling attention to the problem but pointed out that "America's Most Wanted" goes after the most dangerous of the predators.

"There are an estimated 550,000 sex offenders in this country, and more than 150,000 of them are fugitives," he said.

"They know how to use the system to get away with what they do," Walsh said. "Couey, who is a registered sex offender, should never have been allowed around children. He had been arrested more than 20 times [for various crimes], and he should have been in jail."

Walsh said the trial will put a spotlight on how easy it is for sex offenders to beat the system.

He hopes the Adam Walsh Child Protection and Safety Act, which was signed into law last summer, will eventually make the system tougher to beat.

The law, which is awaiting funding and implementation, will expand the National Sex Offender Registry, beef up the federal penalties for crimes against children, make it harder for predators to reach children on the Internet and create a National Child Abuse Registry.