LITTLETON — Tape recordings of frenzied emergency calls released Friday by police testified to the confusion and terror in the Columbine High School massacre and also bolstered suspicion that someone other than Eric Harris and Dylan Klebold was involved in the shooting.

Harris and Klebold are said to have worn long, black trenchcoats during the assault, but Jefferson County Sheriff's Office Deputy Neil Gardner used a different description of one of the attackers.

"He had a white T-shirt on with some kind of a holster vest," Gardner said to a dispatcher after exchanging fire with one of the suspects at about 11:31 a.m.

Though police have not released details of their investigation into other students, they aren't placing any limits on its scope.

"We're not just going to say we've got our two guys and we're done," sheriff's spokesman Steve Davis said. "We're just going to assume there are 30, 40 or 150 people involved until we know otherwise."

The 11-minute tape released Friday includes a call to 911 from a teacher in the school's library — the "killing zone," as one SWAT officer dubbed it, where 12 bodies were found, including those of Klebold and Harris.

"The school is in a panic and I'm in the library. I've got students down. Kids under the table. My kids are screaming, under the table, kids, and my teachers are trying to take control of things. We need police here," said a teacher identified as "Peggy" by authorities — but that name could not be confirmed.

The teacher, who reported an injury to her shoulder when one of the suspects shot at her through a window, told the dispatcher she ordered students in the library to the floor and under tables while an assailant was in a nearby hallway.

"Oh God! Oh God! Kids, just stay down," she cried. "Do we know where he's at? I'm in the library. He's upstairs. He's right outside of here. He's outside this hall. There are lines of people. Kids, just stay down!"

Twelve students and one teacher were killed when Harris, 18, and Klebold, 17, walked through the high school, firing hundreds of rounds from four guns and carrying about 15 homemade bombs. More than two dozen students were wounded.

The two suspects apparently took their own lives with shotgun blasts to the head, ending an assault that some think was meant to level the school.

"That may have been the intent, to destroy this entire building and everything in it," Jefferson County District Attorney Dave Thomas said.

Gov. Bill Owens walked through the bullet-riddled halls of Columbine late Thursday. On Friday, he said investigators are all but certain that the two gunmen had help from others.

"There are backpacks with bombs in there everywhere," Owens said. "The officers in there are convinced there had to be more people involved. There's just too much stuff in there."

Jefferson County sheriff's investigators continue to say they have evidence of only two shooters but are looking "for anybody who may be a suspect," Sgt. Jim Parr said.

Some students have told police there was a third person involved, Parr said, "and we are looking into that."

Sheriff's officials also hope security cameras mounted throughout the school will provide more details of the shooting and bombing spree. However, Davis said, there was no camera in the library.

Furthermore, the time-lapse cameras do not run continuously, and each tape goes back about a week, said sheriff's Lt. John Kiekbusch. Authorities have not yet reviewed the tapes and did not know if the cameras were running during the shooting.

"Ideally they would show the movement and also the actual placement perhaps of some of the explosive devices, prior to the incident," Kiekbusch said. "If that's the case, we have got just very important evidence."

About 150 investigators spent most of Friday huddling and comparing notes from 500 interviews, the team's first chance to trade information and get a glimpse of the bigger picture.

"It's been very, very revealing," Thomas said.

Crime-scene investigators will work until about noon today and then break for the weekend, officials said, as the bomb squad checks student lockers for explosives.

Parr said numerous four-person teams composed of agents from the FBI, Colorado Bureau of Investigation, the Bureau of Alcohol, Tobacco and Firearms and local law enforcement agencies were following the bomb squads through each room of the school and would likely collect thousands of items of evidence.

The sheriff's department expects to remain at the school until at least Wednesday.

Three days into their investigation, officials have identified the weapons used in Tuesday's assault and know where two of them were purchased.

According to Larry Bettendorf, spokesman for the Bureau of Alcohol, Tobacco and Firearms, investigators have recovered two sawed-off Savage 12-gauge shotguns, a 9 mm Hi Point semiautomatic assault rifle and a 9 mm Intra Tec semiautomatic pistol.

The Intra Tec pistol is the descendant of the notorious TEC-9, which in 1994 was classified as a banned assault weapon, according to Bettendorf.

"The shotguns appear to have been manufactured and sold possibly decades ago," Bettendorf said, adding that tracing the two weapons will be difficult.

But ATF agents have determined the two automatic weapons were purchased in the Denver area within the last year and a half, he said. Both guns were bought at legitimate gun shops by separate buyers, who have been identified by investigators.

"It wasn't the suspects who purchased them," Bettendorf said. "Now the job is to find out how they got from the purchasers to the suspects."

Investigators also are interviewing current and former members of the so-called Trench Coat Mafia to learn whether their friends, Harris and Klebold, had help in Tuesday's attack.

And with 1,800 students at Columbine, officials have hundreds of eyewitness interviews to complete. With 500 down, "I expect that to double or triple," said Dennis Goodwin, chief investigator with the Jefferson County District Attorney' Office.

Goodwin appeared in court Friday to argue against unsealing the search warrants obtained this week to search the homes of Harris and Klebold.

"It would not only jeopardize the investigation," Goodwin said, "But I believe it would jeopardize public safety."

District Court Judge Henry Nieto will decide Monday whether to release the warrants.

But court officials have unsealed the two suspects' juvenile records, pertaining to their arrest in January 1998 for breaking into a car.

Klebold "is a bright young man who has a great deal of potential," a juvenile diversion officer concluded a year later. "If he is able to tap his potential and become self motivated he should do well in life."

Columbine freshman Erik Sunde recalled attending Governors Ranch Elementary School and confirmation classes at St. Philip Lutheran Church with Klebold.

"He was really good in Sunday school classes. He seemed like he was pretty religious," Sunde said. "He sort of dropped out of church two years ago."

In an assessment of Harris, the officer said, "Eric is a very bright young man who is likely to succeed in life. He is intelligent enough to achieve lofty goals as long as he stays on task and remains motivated."

The two successfully completed their juvenile probation less than three months ago.

Columbine Principal Frank DeAngelis said he was familiar with Harris and Klebold, but didn't know them well and had no indication that they were a threat.

"The first time I heard of the Trench Coat Mafia was when I heard of it Tuesday afternoon," he said. "I think it was just like any high school where you have several groups with different interests."

Asked about swastikas and other graffiti around the school that may have indicated a problem, DeAngelis said he was unaware of any warning signs.

"Some of the information circulating out there is inaccurate," he added.

President Clinton said Friday that about $1.5 million in emergency federal aid will be available to the victims and families of the Columbine rampage. The $1.5 million grant from the Justice Department's crime victims' trust fund will help pay for funerals, uncovered medical expenses and the lost wages of parents and private mental-health counselors. Gov. Owens has indicated that the state will help with travel costs and other expenses.

Also on Friday, Jefferson County's district attorney appealed to his constituents and the media to help put a stop to the culture of violence.

"Fifteen people met their death on Tuesday of this week in what I believe is one of the single most tragic events in this nation's history," Thomas said.

"If we can't render our schools a safe harbor for our kids to learn, then there is no place that anybody is safe, frankly."

Camera Staff Writer Christopher Anderson and The Associated Press contributed to this report.

April 24, 1999