PORTLAND – Maine’s highest court has upheld a lower court ruling prohibiting the parents of two teenage boys killed when their car was struck by a Cumberland County Sheriff’s Department cruiser from suing for damages.

In a 4-3 decision, the Maine Supreme Judicial Court on Tuesday ruled that the sheriff’s department, the county and the deputy who was driving the cruiser are immune from damages under the Maine Tort Claims Act because the accident took place in the line of duty.

The attorney for Michelle Norton of Flemington, N.J., and her ex-husband, John, had argued that the deputy, Deborah Hall, was negligent when she caused the July 8, 1998, crash by driving too fast without a siren. Hall was responding to what she thought was an emergency call involving an out-of-control child.

Crash experts estimated the cruiser was traveling at about 85 mph in a 55 mph zone when the cruiser broadsided Norton’s car as it turned left on U.S. Route 302 in Raymond. John Norton III, 18, and his 15-year-old brother, Matthew, were killed; Michelle Norton, who was also in the car, suffered minor injuries.

Lawyers for Hall, who is no longer in law enforcement, and the county maintained that state law protected Hall from being sued. The court agreed.

In a dissenting opinion, Justice Donald Alexander wrote that the Maine Tort Claims Act doesn’t relieve governmental entities of responsibility for injuries caused by negligent operation of motor vehicles.

“In the quarter century that the Maine Tort Claims Act has been in effect, we have never held that negligent operation of a motor vehicle directly involved in a collision is subject to discretionary function immunity,” he wrote.

Hall was acquitted of manslaughter charges in the crash, which occurred while the Norton family was vacationing in Maine.

The lawsuit was filed in 2000, five months after Hall’s acquittal.