DENVER – A judge is allowing only one Columbine High victims' lawsuit against sheriff and school officials to proceed.
U.S. District Judge Lewis Babcock dismissed the other claims Tuesday, ruling that authorities responded reasonably to an "unprecedented and rapidly evolving violent situation."
"Holding police officers liable in hindsight for every injurious consequence of their actions would paralyze the functions of law enforcement," he wrote in another of the nine decisions.
Eric Harris and Dylan Klebold shot and killed 12 students and a teacher and wounded more than two dozen others before taking their own lives on April 20, 1999, at the high school near Littleton, Colo.
The remaining lawsuit was filed by relatives of teacher Dave Sanders, who bled to death before rescuers reached him several hours after the massacre.
Telephone messages seeking comment from the sheriff's office and school district officials were not immediately returned.
The victims' relatives and survivors alleged the sheriff's office failed to investigate alleged threats and crimes by the two gunmen a year before the rampage and botched their response.
Babcock's decision came on motions to dismiss filed by the sheriff's department and school officials, who contended they were shielded from liability by the state governmental immunity law.
The Associated Press contributed to this report.