Between the U.S. Post Office and the old courthouse in downtown San Jose is a nicely wrought iron gate with a small white sign. “Authorized Personnel Only,” it says. “No Public Entrance.”

Eighty-four years ago, no gate stood in that passageway, which led to an old jail behind the courthouse. Even had there been, the mob of 5,000 people in St. James Park would have paid it no respect.

They were intent on hanging Jack Holmes and Harold Thurmond, the two men who had confessed to kidnapping and killing department store heir Brooke Hart.

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The 1933 lynching — both Holmes and Thurmond were white, it should be noted — made national headlines, catapulting San Jose, a little-known agricultural town, into the realm of iniquity.

It had a prominent victim, a sudden disappearance, the vengeance of a mob, and profound political consequences. The lynching remains one of the signal events in San Jose’s history, a conspiracy shielded for more than eight decades.

My predecessor as a local columnist, Harry Farrell, wrote a fine book about the subject in 1992, entitled “Swift Justice.” (Used copies are available on Amazon.com for about $24).

Because this is the 25th anniversary of its publication — I decided to pull out my copy of “Swift Justice’’ and follow the path of Harry Farrell in chronicling the lynching.

Here are seven locations that were key to the 1933 lynching: After each, I’ve added a grade to tell you how much of the historic setting remains:

1. De Anza Hotel

The story of the kidnapping of Brooke Hart — Bellarmine and Santa Clara grad, scion of Hart’s Department Store — really begins here, in a 1931 hotel that has been lovingly restored with public help. On Sept. 18, 1933, the head of Hart’s, Alex Hart Sr., held a banquet here to announce that his son, Brooke, 22, had been named a vice-president. The Mercury Herald, the city’s dominant newspaper, duly ran a story. Among the readers of that story, in Farrell’s telling, was Jack Holmes, an oil company salesman and ex-athlete. The idea of kidnapping Brooke Hart was born of his egotism. Historic setting: A.

2. Lightson Alley

A one-block street that runs south from Santa Clara Street, Lightson separated Hart’s Department Store, at the southeast corner of Market and Santa Clara, from the rear doors of the First Street businesses. Around 5 p.m. on Thursday, Nov. 9, 1933, young Brooke Hart left the store, walked down Lightson to a parking lot where he had left his 1933 Studebaker President roadster. Hart drove toward the Market Street exit and vanished.

As the FBI reconstructed the story later, one of the kidnappers leaped aboard Hart’s running board, shoved a gun into his side, and commanded him to drive north. You can sense the shape of the alley but new buildings have changed the scene. (An uncreative eight-story office building sits on the corner where Hart’s once stood.) Historic setting: C-minus.

3. The Holmes House

Jack Holmes was considered the brains of the kidnap plot, a man who dominated his lesser-witted accomplice, Thurmond. On Bird Avenue in Willow Glen, a little north of Willow Street, is an old Victorian that in 1933 belonged to Holmes’ mother-in-law, Alice Fleming. Holmes lived there with his wife, Evelyn, and their two children. His salary helped pay the mortgage for Alice, who labored as a dressmaker. The place is nicely fixed up now, with a picket fence. Historic setting: A-minus.

4. Piedmont Road and Inspiration Drive

A dollop of doubt entered the tale on a four-acre apricot farm that has since given way to the subdivisions of northeast San Jose. A mother and daughter, Delphine and Isabelle Silveria, heard an unusual exchange about 6:30 p.m. on the Thursday young Hart disappeared.

Near the driveway to their barn, they saw a group of five men transfer a young man who matched Hart’s description from a roadster into a long dark sedan like a Buick. “Well, we got him, all right,’’ one of the men with the roadster told the others. Delphine later identified young Hart’s Studebaker as the sporty car she saw.

That raised the possibility that others were involved in the conspiracy — though Thurmond swore in the minutes before he was hanged that he and Holmes had acted alone. Fifty-four years later, Farrell found Isabelle Silveria, then 68, living in southern California. Her story had not changed. Historic setting: D-minus.

5. San Mateo Bridge

According to the confession by Harold Thurmond, he and Holmes conked Hart over the head with a concrete block, bound him with baling wire, and threw him into the water. Weighed down by a couple of concrete blocks, the young heir did not drown right away, and wood-gatherers on the shore heard his plaintive cries around 7:25 p.m. “I can’t last much longer,” he cried.

The bridge has been drastically revised since 1933. But you can get an idea from the eastern stretches how close the shore was — and how easily Hart’s cries could have carried. The young man’s body was discovered ten days later. What inflamed the mob was that his kidnappers negotiated for his ransom after they had already killed him. Historic setting: C-minus.

6. Site of Hart Mansion

The lovely 1920 Hart Mansion, which resembled the Petit Trianon, is no more. It stood at the northwest corner of the Alameda and Naglee Avenue, a spot now occupied by the pedestrian-looking YMCA. In November, 1933, it was the scene of an FBI listening post that tracked the calls of the kidnappers.

One of those calls led to the arrest of Harold Thurmond at the Plaza Garage, south of where the Fairmont Hotel stands now. Thurmond confessed to the crime and implicated Jack Holmes, who was picked up at the nearby California Hotel. The Hart family, which opposed the lynching, was never the same, though the department store lasted downtown for another 35 years. Historic setting: F.

7. St. James Park

The lynching here on Sunday night, Nov. 26, composes the bulk of the action in Farrell’s book. Holmes and Thurmond, who had been moved temporarily to San Francisco’s jail, were returned to San Jose late on Wednesday, Nov. 22. Four days later, inflamed by the discovery of Hart’s badly deteriorated body, a crowd gathered in the square.

Using poles from the Post Office under construction, they rammed the doors of the old jail and took the two men out to the park to hang them: A half-unconscious Thurmond was hanged first from a mulberry tree not far from Trinity Cathedral. Holmes was strung up minutes later from an elm not far from the William McKinley statue. Both trees are now gone.

As for the mob? The lynchers conspired to protect one another afterward. Santa Clara County authorities dropped charges against the only man prosecuted in the lynching, Anthony Cataldi, 18, who boasted to a United Press [comment=”cq”]reporter of getting the rope from his father’s ranch. Much of the old park is still there, though Second Street bisects it now. The lynching makes it a tiny bit eerie. Historic setting: A-minus.