Sometimes I worry 21st-century technology is taking us back to the 18th century when it comes to punishing criminals.

The social media are wild with ideas for frontier justice in the case of three Hawaii students charged with killing and mutilating 15 nesting albatrosses at Kaena Point and destroying their eggs, an unimaginably cruel crime involving baseball bats, pellet guns and machetes.

Christian Gutierrez, 19, has taken the hardest online hits as the only one of the three former Punahou students old enough at the time of the December 2015 crime to be tried as an adult.

Some Facebook vigilantes propose justice from 18th- and 19th-century literature, such as “The Rime of the Ancient Mariner” and “The Scarlet Letter.”

Those with lesser literary pretensions hope he’ll become “somebody’s girlfriend in jail,” get a Singapore whipping or the “North Korean-style justice” of the captured American student beaten into a fatal coma.

An online petition demanding Gutierrez’s expulsion from New York University got 47,000 signatures in a week.

Family Court cases involving the two younger defendants are confidential by law, but their names got out and were blasted over the internet to make sure they’d be marked for life, no matter what the law says.

The defendants’ Punahou ties brought general attacks on “privileged” Punahou students, notwithstanding that the three were turned in by disgusted classmates.

The internet had every bright idea except the obvious one: Let the court do its job, which the court did well in the Gutierrez case.

After he pleaded no contest to counts of animal cruelty, theft and criminal property damage among others, Judge Jeannette Castagnetti rejected his request for probation and a deferred plea acceptance, which would have cleaned his criminal record.

She sentenced him to 45 days in jail starting immediately, a $1,000 fine and 200 hours of community service for a crime she called “shocking” and “cruel.”

Deputy Prosecutor Janice Futa, who had sought a one-year sentence, thought justice was done, as did Lindsay Young, executive director of Pacific Rim Conservation, which manages the albatross colony.

Young told the court how Gutierrez shattered her “life’s work and spirit” and “turned my favorite place on Earth into a crime scene,” but commented later “that any time a young person is sent to jail is a sad day.”

She opposed the petition to expel him from NYU, saying, “We feel that Mr. Gutierrez deserves the opportunity to resume his life once he is released from prison.”

Our legal system was established to be guided by laws and fair processes, not popular opinion and mob rule.

Digital vigilantes who use online shaming and ostracism to exact extrajudicial punishment erase 200 years of progress in equitable jurisprudence.

The internet gives our voices power, but responsible power demands restraint.

Reach David Shapiro at volcanicash@gmail.com.