(Reuters) - A Connecticut state appeals court has rejected an appeal by the parents of two shooting victims of the 2012 Sandy Hook massacre to hold the town of Newtown and its school district liable.

FILE PHOTO: Street artist Mark Panzarino, 41, prepares a memorial as he writes the names of the Sandy Hook Elementary School victims during the six-month anniversary of the massacre, at Union Square in New York, June 14, 2013. REUTERS/Eduardo Munoz

While calling the case “undeniably tragic,” the appeals court ruled 3-0 on Friday against the parents of Jesse Lewis and Noah Pozner, and agreed with a lower court judge that governmental immunity shielded the defendants.

“It is clear that the adoption of the school security guidelines by the defendants was an act of discretion encompassed within their general duty to manage and supervise their employees and the schoolchildren, and, therefore, was protected by governmental immunity,” Judge Thomas Bishop wrote.

The parents had accused school officials of failing to follow mandatory security guidelines that could have saved lives after gunman Adam Lanza shot his way into the Sandy Hook Elementary School on Dec. 14, 2012.

They said these guidelines included the ordering of an immediate lockdown, having doors that could be locked from the inside to keep Lanza away, and ensuring adequate training for faculty and staff.

Donald Papcsy, a lawyer for the parents, said his clients look forward to appealing to the Connecticut Supreme Court.

He said an eventual return to the trial court would provide these “heroic families” a chance to be heard and “keep future kids safer in the process.”

The parents are seeking damages from the defendants.

Lanza killed 20 children and six adults at the school after shooting his mother to death at home. The massacre ended when he committed suicide as he heard police sirens approach.

The case is Lewis et al v Town of Newtown et al, Connecticut Appellate Court, No. AC41697.