Months had passed since anyone had seen her. Winter came and went. Whatever had happened to the woman from Aberdeen, there hadn’t been a sign of her since September 2014.

“She was last seen down beside the sea and the best assessment we had – bearing in mind that she appeared to just disappear off the face of the earth – was that she had gone into the water,” recalls Det Chief Insp Davie Hadden of Police Scotland.

Tragically, Hadden’s hunch proved correct. In April 2015, a fisherman down the coast from Aberdeen, in the north of Scotland, pulled something up in his net. It looked like the top of a human skull. DNA analysis soon proved it was the missing woman, but what had caused her death? Were there any signs of trauma or criminality on the bone?

To try and answer that question, the police turned, as they sometimes do, to the bone experts at Scotland’s University of Dundee.

Britain’s real-life bone collectors are a small band of human anatomy specialists who have set up a bespoke “bones service” for police use – one believed to be the first of its kind in the world. It allows the police to send in pictures of bones that might be dug up during building work, or found outdoors by members of the public. Evidence of murder or a missing person? A quick email to the bones service might be all that’s needed to check.

In this case, Hadden just wanted a further opinion on the skull. His team sent a few pictures of it to Lucina Hackman, one of the bones service’s responders, and later brought it in physically for her to examine. Were there any signs at all that something untoward had happened to the woman?

With the skull having been underwater for months, it wasn’t an easy question to answer. But Hackman could tell the skull was feminine and adult. She could also tell that there were no signs of criminality.

Animal, vegetable, mineral?

Most of the time, photographs that come in to the bones service don’t depict human remains at all. But the police don’t know that. As long as there’s a chance a bone is human, they might have to treat the area as a crime scene and assign officers to the case – meaning a huge cost to the taxpayer and the allocation of precious police time.

But the bones service analysts, who are on call from 7am till 10pm seven days a week, often reply within minutes. Just by glancing at a photo on her phone, laptop or iPad, the service’s founder Sue Black can usually tell if it’s a human or animal bone. Sometimes, an answer will be ready for the police in about as much time as it takes to boil a kettle.

When the service was launched in 2008, there was no other facility like it in the world

The service also has always been free – and Black intends for it to remain so. She sees it as a crucial link between the university’s forensic science department and the police force, as well as a teaching tool for her students.

When Black launched the service in 2008, there was no other facility like it in the world, at least that she knew about. It has quickly become popular. The service now deals with some 450 cases annually. They come in from all over the UK and further afield. Pathologists and police officers who have emigrated have taken knowledge of the service with them, so occasionally requests from Canada, India and Australia come in, too. Black’s team replies to them all.

But UK police officers are those most familiar with the facility. Britain’s landscape is rich with skeletal deposits, it turns out. A combination of the country’s history and its unpredictable weather means that remains are constantly getting exposed. Around Scotland, for example, Hackman says there are a lot of beach burials – which high tides and winds tend to uncover.

Pictures of seal flippers especially come in fairly regularly, Black says. A decomposing seal flipper on a beach looks freakishly like a human hand.

How do anatomists tell the difference? And how do they learn to do it so quickly, from photos often just taken with a mobile phone’s camera?

A decomposing seal flipper on a beach looks freakishly like a human hand

“We have to be as familiar with marine species as we are with terrestrial species, as we are with those species that fly, and those that are pets compared to those that are farm-based,” says Black. “It goes right the way across the whole spectrum.”

This is why collecting bones is important.

Skeletons in the closet

In the facility is a store room full of containers. Some of them look like they could easily hold rice and curries – air-tight takeaway boxes, it turns out, are perfect for storing smaller bones. The specimens inside range from cattle skulls to foxes, dogs, cats, chickens, dolphins, birds, sheep, deer and even minks, the otter-like animals which live in and around Britain’s rivers. Boxes indicate whether a complete set of bones is contained within, or if the specimen is missing a few. One container is labelled “assorted feet”.

Over the years, Dundee has built up this collection through donations and even, now and again, by taking in roadkill.

One container is labelled ‘assorted feet’

In another room, Hackman lifts the lid off a large white box to reveal a grisly sight – hundreds of dermestid beetles scurrying around on a pile of bones.

“Their job is to strip the tissue off,” says Black. “So if someone is to hit a rabbit on the road they’ll take the rabbit in to us.” The bone collectors will skin it and put the carcass in with the beetles.

It’s knowledge of these specimens, and how they decay, that make Black’s rapid-fire analysis possible.

Back in her office, she brings up the archive of past requests from police forces in the UK and elsewhere in the world. She opens a file that came through the previous day: a grubby-looking bone that appears to have been interfered with. “It’s been cut with a fairly coarse saw,” she says.

She clicks on another image. The shape of a jawbone appears. “Ah, OK, so it’s human,” she says. “It would have been nice to take the mud off,” she adds. Sometimes the police neglect to clean up the remains; now and again the pictures are out of focus.

In this case, the bone is human but likely archaeological. Of all the hundreds of cases that the bones service receives each year, just one or two might be human and also recent – adding up to a huge savings of police time and money. Now, the bones service will tell the police and recommend they ask a local archaeologist if it’s a known burial site.

Crime scene or archaeological site?

If there’s any doubt about the age of the remains, they can always be dated with chemical analysis. One such service is provided by Gordon Cook at the Scottish Universities Environmental Research Centre’s radiocarbon dating lab. Cook’s lab is able to take a few milligrams of collagen from bones, then extract and analyse the carbon to see how much carbon-14 is present.

Carbon-14 is a good indicator of the specimen’s age because of a slightly sinister reason - nuclear bombs.

“From around the mid-1950s to the early 1960s, there were a number of nations who did atmospheric testing of nuclear weapons and one of the by-products of that is carbon-14,” Cook says. “That signal gets into the plant material very readily, from plants to animals, animals to humans. So anyone who has lived during the nuclear era […] will have an enriched carbon-14 signal.”

Carbon-14 is a good indicator of the specimen’s age because of nuclear bombs

Because of nuclear test ban treaties, atmospheric weapons testing has ceased, meaning that this type of analysis won’t always be as useful. For now, it’s also tricky because collagen in human bones gets gradually replaced over time by the body, so the amount of carbon-14 isn’t a precise indicator of the dates of birth or death. In teeth, though, the carbon-14 is laid when the tooth is formed and doesn’t change, which often allows Cook and his analysts to work out the birthdate to within a year or two.

Although many of the cases Cook and Black deal with are non-modern – or, in Black’s case, non-human – bones, when their services play even a small role in an active case, the effect can be critical. The case of the Aberdeen woman is just one such example.

“When you talk to families of missing people, they talk about their life in a stutter that they just can’t get beyond. And when you find somebody, it’s sad news,” says Black, “but there’s a kindness in that.

“You’ve taken away the hope. But at least you’ve got reality.”

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