"Those basement videos tell why those two murderers were going to do this crime, how they were going to do it, and when they were going to do it," Rohrbough said at a news conference held outside the Jefferson County Sheriff's Office on Friday.
Friday was the eighth anniversary of the Columbine shootings.
The Jefferson County Sheriff's Office will not release the tapes in part out of the fear of copycat murders.
"(The tapes) were actually reaching out as a call to arms to other kids or people who felt the same way (as Eric Harris and Dylan Klebold) and this is how (other people) should act," said Jefferson County Sheriff Ted Mink.
Last year, Mink decided to release a huge amount of previously undisclosed documents used as part of the investigation, but he decided he would not release the basement tapes.
The tapes were made by Harris and Klebold in the weeks leading up to the 1999 shootings at Columbine.
Mink says the release of Seung-Hui Cho's videos and pictures this week by NBC has led him to believe he didn't err in his decision.
In fact, he said on Friday, "It makes me even more convinced that I made the right decision in not releasing the Columbine tapes."
Rohrbough says that is simply a terrible mistake.
"(The tapes are) the best information we have to identify the threat," he said.
He also criticized the recent decision by federal Judge Lewis Babcock to keep the depositions of the parents of the Columbine killers sealed for the next 20 years. Babcock, in his decision, also worried the release of the depositions could lead to a copycat crime.
Harris' and Klebold's parents have never publicly told their story, a decision that has deeply upset many parents of the Columbine victims.
Rohrbough and Rich Petrone (stepfather to Columbine victim Dan Rohrbough) angrily disagreed with Babcock's decision on Friday.
"We need help!" cried Petrone, acknowledging an appeal of Babcock's decision is possible yet potentially too costly to go forward with.
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