PEOPLE had “suffered together and grown stronger” as a result of the Columbine shootings, which killed 14 students and a teacher, according to the head of the district’s schools, Jane Hammond.

Ms Hammond’s feelings were echoed by others at the ceremony to mark the first anniversary of the killings at the Colorado high school - the worst school shooting in American history.

But the speeches about solidarity and mutual support took place amid bitter conflict between relatives of the dead and the authorities. They have filed a wave of lawsuits accusing the police of ignoring vital warning signs that should have helped prevent the killings; suits against the school and other authorities are expected to follow.

Michael Shoels, whose stepson was killed in the shootings, has sued the sheriff’s department and the parents of the two teenage gunmen. He attended the memorial ceremony but stood at a distance.

“I felt obligated to come here today with a message, to say it’s time for changes, time for parents to protect their children, time for parents to take back parenthood, to be parents and stop the destruction of our children,” he said.

So far, nine suits have been brouht against the sheriff’s department. Most were filed on the eve of the anniversary because of a Colorado law that sets a one-year limit on suing the police. However, more claims are expected against the school district and related agencies.

The most serious accusation has come from the family of Daniel Rohrbough, one of the first students to be shot. They claim he was killed by a stray bullet fired by a deputy sheriff - and not be either of the gunmen, Eric Harris and Dylan Klebold. Harris and Klebold, who were also students at the school, took their own lives after the shootings.

Parents of the victims also claim that the sheriff’s department knew a pipe bomb had been found in Harris’s possession 14 months before the killings, but took no action.

Another lawsuit, filed by the daughter of the teacher who was killed, said he was allowed to lie wounded at the scene for hours and bled to death because of police inaction.

The county attorney, who represents the sheriff’s office, said the claims were baseless.

The anniversary was also marked by fears of copycat violence that forced the closure of schools in other states and the arrest of at least one student.

President Clinton has announced $120 million (pound;76m) in new federal grants to put more police officers in schools.