The verdict is in.

Court officials have determined that a portrait of a previously unnamed judge hanging outside the chambers of Chief Justice Ralph D. Gants of the state Supreme Judicial Court depicts the Honorable Lemuel Shaw, who held Gant’s position from 1830 to 1860.

The break in the case, which befuddled and fascinated local historians, was announced in a statement Thursday from the SJC, which had issued a rare public appeal in February for information leading to the judge’s identity.

“Thanks to the forensic work of Trial Court Assistant Chief Court Officer Keith Downer and our Director of Education and Public Programs Cliff Allen, we have been able to identify the subject of the portrait as the Honorable Lemuel Shaw in his younger years,’’ Gants said in the release. “The remarkable level of interest among members of the public and over 40 submissions received is an example of civic engagement at its best.’’

Shaw, the father-in-law of Herman Melville, ruled on a range of issues during his tenure, including slavery, school segregation, business law, and labor relations. He ruled in an 1836 case that a slave brought voluntarily into Massachusetts, then a free state, was effectively free from bondage, an opinion cheered by abolitionists.

“It is upon these grounds we are of opinion, that an owner of a slave in another State where slavery is warranted by law, voluntarily bringing such slave into this State, has no authority to detain him against his will, or to carry him out of the State against his consent, for the purpose of being held in slavery,’’ Shaw wrote at the time, according to a transcript of the ruling posted on the University of Florida website.

But his ruling in another case in 1851 upheld the Fugitive Slave Law.

“Although personally opposed to slavery, Shaw believed that it was ‘too deeply interwoven in the texture of society to be wholly or speedily eradicated,’ ’’ said an entry on the website of the Smithsonian’s National Portrait Gallery. “In 1851 he issued an opinion supporting the constitutionality of the Fugitive Slave Law of 1850.’’

In seeking the identity of the mystery judge, court officials received a total of 42 informed guesses, the SJC said. The tipsters named 24 people, but not all of them had served on the SJC, according to the statement.

Ten guesses came in for Shaw; four for Thomas Dawes; three for Samuel Sumner Wilde; two for Ethan Allen Greenwood; two for Simeon Strong; two for Levi Lincoln; and two for Marcus Morton Sr. to round out the top tier, the SJC said.

Officials credited Downer with cracking the case by employing his expertise in forensic science and deep knowledge of antiques and fine art.

Downer made a visual inspection of the painting and did limited research without seeing any of the informed guesses, the SJC said. Then he really drilled down.

“He found that the very basic and obvious features narrowed the painting to a small field of study,’’ the statement said. “Following the visual examination, he conducted a UV light absorption or reflection test using a UV-A (blue or black light), which allowed him to see things the naked eye cannot. Next, bright yellow and bright white light tests allowed those present to see the loop script initials ‘L S’ become visible on the top rail of the stretcher.’’

Call it the smoking gun.

The equipment Downer used will be shown at an event April 10 at the John Adams Courthouse, where Gants will attach Shaw’s nameplate to the portrait. The 10 people who guessed Shaw are also invited to attend, the statement said.

They’ll be treated to a tour of the historic courthouse, led by Allen.

“While it may be impossible to conclude with 100% certainty the true identity of the justice, the court believes that the most persuasive arguments, confirmed by the forensic report that the court has received, point to a younger Lemuel Shaw whose portrait was painted before or around the time he was appointed to the Supreme Judicial Court in 1830,’’ the release said.

Legal luminaries praised Shaw during a 1930 ceremony in Massachusetts marking the 100th anniversary of his appointment to the SJC.

Frederick H. Chase, speaking on behalf of the Boston Bar Association, was particularly effusive, according to a transcript of his remarks posted to the state website.

“The master of his century was Lemuel Shaw,’’ Chase said. “ . . . No one has done more to help us to keep our faith in the living force and beauty of the common law. He gave enduring assurance to society that judicial pronouncements come as the result of profound knowledge, earnest human consideration, and deliberate conviction.’’

Ironically, Chase also gushed over portraits of the celebrated judge.

“His portraits even, so familiar to us all, carry conviction of his power,’’ Chase said. “As we look at his likeness we are reminded of the legendary Greek who, when asked how she knew that Hercules was a god, replied, ‘because I was content the moment my eyes fell upon him.’ ’’

Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.