LITTLETON, Colorado (AP) – As they prepared to mark the anniversary of the Columbine school shooting eight years ago and a shooting at Virginia Tech earlier this week, many Littleton families are questioning a judge’s decision to seal information about the killers.

Columbine High School will be closed Friday as it has been every April 20 since the 1999 school shooting in which two students, Eric Harris and Dylan Klebold, killed 12 classmates and a teacher before killing themselves.

Invoking the Columbine tragedy, the Governor of Colorado, Bill Ritter, asked state residents to join a nationwide bell-ringing and moment of silence for the Virginia Tech victims on Friday.

“We experienced a terrible tragedy at Columbine High School,” Mr. Ritter said. “The people of Colorado will stand in solemn silence on the anniversary of that dreadful day with the people of Virginia as they grieve.”

But federal Judge Lewis Babcock’s decision earlier this month to seal for 20 years testimony from the parents of Harris and Klebold about the boys’ home lives has infuriated some survivors and victims’ relatives, who feel the information could help prevent future school rampages.

“I don’t think you can stop every crazy person. But some of the things Babcock locked up show what these crazy kids did,” said Don Fleming, whose 16-year-old daughter, Kelly, was killed. “It’s no use to anybody if it is locked up.”

“If society knew, it could possibly prevent future shootings,” Mr. Fleming said. “We’re finding out that everything that the latest killer did is similar to what Klebold and Harris did.”

Cho Seung-Hui, who killed 32 people on the Virginia Tech campus on Monday before taking his own life, called Harris and Klebold “martyrs” in a videotape he mailed to NBC that was broadcast Wednesday.

In his ruling, Judge Babcock cited a need for confidentiality and concerns that releasing the testimony from the Columbine killers’ parents could encourage copycat crimes.

Many in this suburb of Denver think the decision was a mistake.

“Are the people of Virginia going to wait 20 years?” said Dawn Anna, whose 18-year-old daughter, Lauren, was slain at Columbine.

For some here, watching events unfold in Virginia was a painful reminder of the chaos and suffering thrust on them eight years ago. The parents of students slain at Columbine met this week to deal with the shock of the Virginia killings. The judge’s decision dominated their conversation.

“I felt like I was looking at Lauren’s murderer. It’s as if someone has been cruelly replaying April 20,” Ms. Anna said.

The Harrises and Klebolds comment publicly only through their lawyers. Michael Montgomery, an attorney who represented the Harris family, said that the judge “made an absolutely appropriate decision.”

In his ruling, Judge Babcock said: “I am mindful that there is a legitimate public interest in these materials so that similar tragedies may hopefully be prevented in the future. I conclude, however, that the balance of interests still strikes in favor of maintaining strict confidentiality.” He also said he feared the information could lead to copycat attacks.

Judge Babcock declined comment Thursday.

Much information about the Columbine killers is available on the Internet, including video clips of the two practicing their marksmanship, Harris’ diaries, and Web sites dedicated to both killers.

Authorities did learn that Harris and Klebold played violent games, made violent videos at school, and were bullied.

Researchers into school-related violence support the Columbine victims’ stand, noting the relative frequency of violent campus incidents. The Centers for Disease Control reported in 2002 that there had been 220 school-related shootings from 1994 to 1999, resulting in 253 deaths.

“The judge said the tapes were incendiary. We have plenty of things already that stimulate violence,” said sociologist Ralph Larkin, author of a recent book on the Littleton slayings, “Comprehending Columbine.”

Katherine S. Newman, a professor at Princeton and author on shooting rampages, said the information should be released.

“A 20-year lag deprives the rest of the country of what might be valuable insight. Indeed, having done a lot of research with the families of victims, they are left with a big hole in the middle not only by the loss of their children but by the unanswered ‘why’ questions,” Ms. Newman said.