PORTLAND — Maine’s highest court will likely have the final say on another challenge of the state’s sex offender registry after 16 sex offenders lost their latest effort in Superior Court to be removed from or stay off the list, attorneys for the state and the offenders said Monday.

Late last week, Superior Court Justice Michaela Murphy dismissed a challenge to the sex offender registry brought by 16 plaintiffs, who are known in the lawsuit as John Doe. Among other things, they argued that the law shouldn’t be applied retroactively to their cases.

The ruling was the latest step in a complicated issue – which has been addressed in the courts and the Legislature – asking which sex offenders should have to register with the state, and how best to balance an individual’s rights with the public’s interest in protecting people, especially children, from sex offenders.

Deputy Attorney General Paul Stern said he’d be surprised if the plaintiffs didn’t appeal Murphy’s ruling to the Maine Supreme Judicial Court.

“The legal issues are complex. But I think that’s reflective of the enormous societal issues,” Stern said.

Attorney Walter McKee, who represents one of the plaintiffs, said the primary argument in the case was that Maine’s Sex Offender Registration and Notification Act violated the plaintiffs’ rights by requiring them to register as sex offenders even though the law didn’t exist when they were convicted.

McKee’s client, John Doe XIV, was convicted of gross sexual misconduct in 1983, served less than a year in a county jail and then went on with his life, McKee said. In 2009, he was told he had to register as a sex offender for life. He is on the registry.

“I think everybody involved in the case is taking some time to go through the extensive detail and analysis in the court’s order,” McKee said of Murphy’s 70-page decision. “Unlike other cases where you can quickly say we’re going to appeal, this one’s going to take a little more time.”

Jim Mitchell, an Augusta lawyer who represents 13 of the 16 plaintiffs, was out of the office Monday and could not be reached for comment.

Maine’s sex offender registry has gone through a number of changes since it was created in 1992. It attracted national attention in 2006 when a 20-year-old Canadian man killed two sex offenders in Maine before killing himself after randomly getting their names from the state’s online registry.

The case before Murphy stemmed from a 2006 court case challenging the law. Over time, several dozen John Does joined the case, but a number of them later dropped out after the Legislature amended the law, allowing some sex offenders to be removed from the registry if they completed their sentences, committed no additional crimes and met other standards.

Many of the remaining plaintiffs in the lawsuit, however, are not eligible to have their names removed from the registry.

McKee said his client and other plaintiffs would have used a different legal strategy and possibly demanded a jury trial rather than plead guilty if they’d known in the 1980s that they would have to register on a public sex offender registry for their crimes.

An appeal might be developed on the premise that sex offenders deserve a chance to have their names removed under Maine’s Declaration of Rights if they can prove they’re rehabilitated and have achieved civic redemption.

“My hope is that if the Declaration of Rights issue can be developed, then the Supreme Court will use that as an opportunity to address the wrong that was committed here,” he said.

The Declaration of Rights argument was raised unsuccessfully in a previous sex offender registry case that reached Maine’s Supreme Court, Stern said. Congress and state legislatures have agreed that states have the right to create registries to protect the public from sex offenders, he said.

“If a person moved next door who was a sex offender in 1983,” he said, “wouldn’t you want to know that?”