How hard could it be to solve a 100-year-old murder mystery?

Involving a history writer, a State Police detective, and a cold case on the shores of Farm Pond.

Holly Nadler investigates on Farm Pond, the scene of the century-old murder. - Sam Moore

It was a dark and stormy night.

Naw, it was a hot night, July 10, 1916, when a 36-year-old woman named Henrietta McLeod, originally of Milton, disappeared from Oak Bluffs. She’d been working as an au pair, or what they called in those days a “nurse girl,” in Boston for a Dr. and Mrs. Luttropp and their kids, having accompanied them to their summer home. Her disappearance turned into one of the juiciest murder mysteries that has ever gone unsolved on Martha’s Vineyard (well, maybe one of the only murder mysteries gone unsolved). Inspired by a story “This Was Then” columnist Chris Baer wrote in this paper (April 7, “100 years ago, a Tivoli girl”), I decided I’d like to find out what it takes to solve a murder mystery. Especially one that’s been around for a century.

Here’s what we know from stories that appeared in the Vineyard Gazette, which then “went viral,” as the story of the suspected murder was picked up by the Boston Globe, the Boston Post, and as far afield as the Washington Herald:

Miss McLeod — can we call her Henrietta? — had been summarily fired by the Luttropps on the grounds she was a poor cook. Truly? She’d worked for them for several weeks, and now they determined she had no idea how to poach an egg? Told to go, she plopped her colorful Panama hat over her head, and departed with her wicker valise, dressed in a black skirt and a white button-down shirt. The Luttropps said she appeared to be in a “daze.”

Duh. She had $3 in her pocket, a train ticket for the trip back to Boston, and knew no one on Martha’s Vineyard. She was last glimpsed by a couple of milkmen on the day she was sacked, a Sunday. She milled around the docks near the steamer, then changed course and headed for William Ripley’s lunch cart. Her sandwich must have set her back about 25 cents, so she was down to $2.75, which, in those days, could stretch for a week.

Two weeks later, on July 25, Mr. Ray Wells, manager of the popular dance hall the Tivoli, took a morning stroll along the banks of Farm Pond. At a remote, heavily wooded area far from any houses, he saw what he first identified as a soggy bundle of clothing in the water.

The bundle was the badly decomposed, bloated remains of Henrietta McLeod, wearing nothing but her undergarments (my Grandma Mae would have called her “half naked”). The ID was simple: Her name had been handwritten inside the waistband of her underpants.

In addition to her clothes, she was missing a gold ring, and her upper and lower front teeth. No other signs of assault were described in the newspapers. The media was most discreet in those days. An autopsy revealed her lungs were empty of water, so she’d died from something other than drowning. If this doesn’t scream “homicide!” then Lizzie Borden never gave her dad 40 whacks.

State Police Inspector Thomas Dexter of Edgartown believed Henrietta had been murdered, hence the attention of big-city papers with headlines such as “Girl’s Body Found in Pond Near Resort” and “Bellevue Nurse Girl Murdered.”

And yet, within a few days, because Henrietta’s suitcase, bedding, clothes, and a torn, unreadable letter were found by Boy Scouts in the woods around Farm Pond — yes, she had apparently been bivouacking in the wild: Brave woman! — and because the respectable Luttropps (husband a dentist and professor at Tufts) described her as acting “peculiar” in her last few days (what happened to the charge of bad culinary skills?), the local police filed the case away as a suicide.

Henrietta’s sister, who came down from Milton to fetch the body, was indignant: Her sister had been strong, with good teeth. How does a woman commit suicide by punching herself in the mouth, and then — what? — hurling herself in the water, and holding her breath to avoid drowning?

So when I read a few months ago about this unsolved murder of the Tivoli girl in the Times, I decided to jump into this case with my vast knowledge of police forensics, gleaned from tens of thousands of hours watching “Law & Order,” “Breaking Bad,” “The Wire,” and of course, “Columbo”: “Uh, just one other thing …” I knew that today, with a “floater” like Henrietta McLeod, modern detective techniques could wrap this case up in 24 hours. First the lead investigator would escort the dentist into an interrogation room, offer him coffee, then work him over for five or six hours, with questions along the lines of, “Were you and Miss McLeod having a —” (What did they call it then? A shag? Probably not.) “Did Mrs. Luttropp find out? Is that why you fired the girl?” “Did you have dalliances with her in the woods?”

Then, of course, modern forensic science would have Hoovered in, DNA would be disclosed, along with fingerprints, Model A Ford tire marks, and “Voilà!” As Inspector Hercule Poirot would have cried, “My leetle gray cells have found zee killer!” It could have been a homicidal daytripper! Or, not Dr. Luttropp, but his dental hygienist.

Here’s how I took it upon myself to solve the crime: As in your classic drawing room mystery, I borrowed my friend Sharon Kelly’s Victorian parlor facing Ocean Park — and in the distance, the site that once housed the Tivoli Dance Hall, whereabouts Henrietta was last seen. I invited Sharon’s friend, Trooper Dave Mackin of the Massachusetts State Police Southwest Crime Lab in Lakeville. He’s “the guy” — the guy who’s summoned here to M.V., and all over Massachusetts, whenever a body turns up with “foul play” stamped all over it in red ink. I also assembled my esteemed colleague, Chris Baer, who resuscitated this mystery from the mists of time, and Sharon Kelly because, uh, she already lives there. Plus she’s insightful and super-smart!

Here’s what Trooper Dave would have done with a deceased Ms. McLeod in 2016: He and his team would have roped off the crime scenes — the banks of the pond, and Henrietta’s crumpled camp. The medical examiner would take scrapes from the dead woman’s fingernails. They’d dust for fingerprints, and spray chemicals for trace evidence on Henrietta’s clothes and bedding. And, yes, he affirmed: Investigators do snap on plastic gloves before they get to work, just as they do in “Bones”!

What about Henrietta’s torn letter? Trooper Dave assured us they could have reassembled it, dusted for fingerprints, and swabbed for DNA.

Trooper Dave said he’d have eight or nine detectives on the team. They could knock on doors and scout for clues. Yes, they still say the word “clue” in law enforcement, but with an ironic twist, admits Trooper Dave with a chuckle: Arthur Conan Doyle got us hooked on it.

Our crack investigator was under orders not to incriminate anyone in any way. But that hardly stopped our crew of amateur sleuths — Sharon, Chris and me — from speculating wildly. None of us could resist connecting the dots between “missing teeth” and “dentist.” (Probably a 100-year-old coincidink).

Let’s not forget, however, that in the classic mystery, it was always the dentist. No, wait. It was always the butler.

Trooper Dave reminded us of today’s ubiquity of CCTVs (that’s closed-circuit TVs to the uninitiated) and cell phone cameras. He called our attention to a statement from the Boston Globe of July 27, 1916: “Officer Dexter believes she was enticed away from the dock by [one of the] shady characters who loiter around that section, to some lonely place, and slain.” Henrietta’s movements could have been picked up from cameras at the dock, at the Tivoli, and heading out of town. Whoever lured her away would have been caught dead to rights, as so many criminals are today — by enough mug shots to make a movie.

Here are some fun facts we learned in our two hours in Sharon Kelly’s exquisite Front Parlor/Murder Room:

When checking for shoe or boot prints, the No. 1 shoe worn by criminals is Nike Air Force 1! (A word to the unwise: Time to change your footgear.)

Some people shed more DNA than others. Trooper Dave worked with a bald detective whose shiny pate strewed skin cells like an open can of Ajax. For a while it looked as if the team had a serial killer on their hands, until they learned to keep the bald detective from murder scenes.

Our little Island is relatively free of violent activity, as we well know: In Trooper Dave’s 14 years on the job, he’s only been called here for two murders (although he’s frequently imported here, there, and everywhere for dead bodies turning up without a clear-cut cause of death).

On his mainland turf, he and other troopers are coming up against a rash of random body parts stashed in dunes and empty lots. It doesn’t take a Miss Marple to determine something sinister is afoot.

At the end of our consultation, Chris Baer and I walked Trooper Dave along the banks of Farm Pond. On a short landing, I applied my magnifying glass to the foot-deep water, just in case Henrietta’s lost gold ring might have chosen this synchronistically charged moment to reappear. It had not.

Our next step will be to reach out to descendants of Henrietta’s who might possess some family lore. Mr. Baer put me in touch with a great-grandniece, Louise Tremblay of Dracut, who, while fascinated to learn about her death-by-dubious-circumstances ancestor, had heard nothing, ever. She promised to check around with her cousins.

Chris and I will see if any police records exist in some moldy municipal basement. If we find anything, our book, “Tivoli Girl,” will be out next summer. Look for it in local bookstores.