In a snowy, wooded area in Colorado, the two teenage Columbine High School (search) shooters laugh as they fire round after round at bowling pins and trees and wonder aloud what it would be like if real people were their targets.
This chilling scene is in the so-called "Rampart Range" videotape, released Wednesday and made March 6, 1999 — six weeks before Dylan Klebold (search) and Eric Harris (search) carried out the horrific high school massacre.
"Imagine that in someone's [expletive] brain," Harris says in the video, examining damage done by a bullet to a bowling pin.
The two teens walked into Columbine High on April 20, 1999, with a collection of guns and explosives and killed 12 students and a teacher before committing suicide. It was the worst school shooting in U.S. history.
Jefferson County sheriff's officials decided Wednesday they would make the video public in the wake of calls from the Columbine Open Records Task Force (search) to release more information about the shootings. Officials contacted the families of victims to let them know.
County officials have been widely criticized for ignoring several warning signs that the attacks were coming — among them, death threats by Harris against other students and a psychological profile of Harris in which he reported feeling "suicidal and homicidal."
Some parents blasted officials Wednesday for keeping the videotape out of the public eye for so long and suggested that a cover-up was taking place.
"Why would they not want this information public? Why wouldn't they want to help school systems and police all over the country?" asked Randy Brown, the father of a student who was at Columbine during the rampage.
Brown -- who is on the Open Records Task Force -- told Fox News that he believes Klebold's and Harris' parents, the school and law enforcement were all trying to conceal information.
Judy Brown, Randy Brown's wife, said other tapes existed, including a voice recording that allegedly has both Klebold and Harris discussing what they intended to do at the school.
"The videotape is important," said Randy Brown. "What's really important is did the sheriff see it, did the school see it, or did the parents see it? How many opportunities were missed to stop these two killers?"
Laughing and Shooting
The disturbing, 15-minute tape shows Klebold, Harris, another young man and a young woman doing target practice at a makeshift shooting range in a forested area in Douglas County, Colo.
The group can be seen firing several rounds from rifles, shotguns and a 9 mm semiautomatic pistol at bowling pins, trees and other targets. Police said some of the weapons were used in the Columbine attack.
They can be heard laughing, joking and making cavalier comments about what it would be like if the bowling pins were human heads or bodies.
The video, taken on a shaky handheld camera on a snow-covered hillside in a national forest southwest of Denver, is the first made by the gunmen themselves to be released to the public.
Klebold at one point holds a sawed-off shotgun and shoots from the hip at a bowling pin wedged between two tree limbs. He and Harris then look at a bullet-shredded tree trunk.
Harris also blows across the muzzle of a shotgun like a gunslinger. At least four different weapons are used in the tape.
Both teens wear trenchcoats, and later show the camera hands made bloody by a gun butt.
"Guns are bad. When you saw them off and make them illegal, bad things happen to you," one says. The two then point at a gun and mockingly spank it as Klebold says, "no, no, no."
The two repeatedly point to shattered bowling pins and giggle about entry and exit holes. The boys were in a bowling class hours before the shootings began.
The videotape has never before been made public, though Brooks Brown, one of Klebold's friends and the son of Judy and Randy Brown, told Fox News that several people had told him the tape was shown before the massacre in Harris' and Klebold's video class.
The homemade tape was released at the urging of the Jefferson County sheriff's office and a task force established by the attorney general's office, both of which want to make evidence in the case public.
The sheriff's office earlier released surveillance video showing Harris and Klebold as they entered the high school cafeteria during their rampage.
Brooks Brown was one of the people Harris threatened to murder on his Web site, just over a year before he went on the rampage with Klebold.
"He went into detail about how he would gladly pay a price to cut my head off," said Brown, who immediately notified the police. "It was horrifying stuff."
Brown, who has written a book on Columbine entitled "No Easy Answers," said he had no inkling that Harris and Klebold had a cache of weapons.
"I knew nothing about the guns," he said on Fox News. "They wouldn't have told me anything."
The videotapes were used as part of the case against Mark Manes and Philip Duran, two friends who got Harris and Klebold one of their guns. Manes appears in the video; Duran filmed it.
The video shows Manes shooting some of the weapons. Manes sold Harris and Klebold a TEC-DC9 semiautomatic handgun used in the attack for $500 about three months before the massacre.
The men were in their 20s at the time of the Columbine rampage.
Manes pleaded guilty to providing a handgun to minors and possessing an illegally sawed-off shotgun and was sentenced in 1999 to six years in prison. He was released to a halfway house after less than two years.
The young woman in the video was Jessica Miklich, Manes' girlfriend. The video shows her shooting one of the rifles, a trenchcoat hanging on a tree in the background.
The man who taped the target practice was Duran, who worked with Harris and Klebold at a pizza shop, Jefferson County district attorney's spokeswoman Pam Russell said.
Duran, who was accused of introducing Harris and Klebold to Manes, was charged with providing a gun -- the TEC-DC9 -- to a minor and possessing a dangerous or illegal weapon, a sawed-off shotgun. He was sentenced in June 2000 to 4 1/2 years in prison.
In a videotaped message before the attack, the gunmen thanked Manes for providing the gun, saying they couldn't have done it without his help. They also warned him that he and Duran would probably be blamed for helping with the assault.
Lawsuits to release the so-called "basement video tapes" -- made by Harris and Klebold in the months before the attack -- are pending. The sheriff's office has allowed reporters to watch the tapes, but has not released copies to the public.
Fox News' Carol McKinley, Catherine Donaldson-Evans and The Associated Press contributed to this report.