There are 100,000 missing people in the United States alone and at least 6,000 unidentified bodies. With the authorities struggling to solve so many cases, thousands of volunteers are using the internet to try to match the missing with the unidentified. Internet sleuth Todd Mathews reports.
It all started for me with the "Tent Girl", so called because her body was found wrapped up in a canvas tent bag. I heard about the case when I first met my future wife Lori at school.
After lying unnamed for 30 years, Tent Girl's name was added to her grave
She had come to Tennessee from Kentucky and told me how her father Wilbur Riddle had found a murdered girl in a field near Georgetown in the 1960s.
Her name, Tent Girl struck my soul. It was as if it were almost familiar. As Lori and her family became part of my own family, so did the Tent Girl. Two of my siblings died of natural causes as infants early in my life. She was no different to them in my mind.
I had a place to visit my siblings, but Tent Girl didn't have any family. So she became part of my own family. And I became determined to find out who she was.
I went to her grave many miles away in Kentucky. I visited newspapers in the area to look through hard-copy archives, searching both for stories about the Tent Girl, as well as any accounts detailing a missing person that matched her description.
For 10 years that is how I conducted the search. I spoke to investigators and journalists by phone or in person, looking for any shred of data. I felt so close yet so far, as if the information was just outside my field of view.
Wilbur and Todd are to appear in a documentary film featuring 'Tent Girl', entitled Resurrection
As I worked, I also learned many things about how to search for information.
When the internet arrived, the main thing it changed was communication. In the early days the vast online resources available today did not exist. But I could do my searches by e-mail, and information about how to contact government and media offices was easier to find.
Research was much easier, more affordable and realistic. Distance was no longer an obstacle.
But perhaps more important was that it ended the isolation of individual investigators. Once the World Wide Web connected the planet, a natural gathering took place. I found other like-minded people doing the same kind of work.
The internet gave us an opportunity to gather and share information, to work on a common cause. We could cross the globe in seconds with a click of a computer mouse.
Yahoo-based Cold Cases group was one of the first of these such "virtual" gathering places and out of it grew organisations such as the Doe Network, so called because John or Jane Doe is the name used by the FBI for the unidentified.
An unidentified body in Tennessee is exhumed for DNA testing
Over the past decade, an increasing number of websites devoted to particular cases of missing persons have been created. One of the first was my own for the Tent Girl.
There were more people coming online daily with missing pieces in their lives. Message boards intended for other uses were being used to post about missing persons and lost loved ones.
It was a night like a thousand nights before, when I found what I was looking for at last. I had found a posting by a woman looking for her sister last seen in Lexington, Kentucky. I read on.
The description was matching the description etched onto the Tent Girl's headstone. The feeling in my heart was greater than the evidence I was reading on the screen. A decade of burden was lifting away and I knew deep inside this was her at last.
Rules and methods
Tent Girl finally had a name. She was Barbara Taylor, a wife and mother when she died. By now, she would have been a grandmother.
It was one of the most profound and fulfilling moments in my life. And, I was soon to find, it would have a deep impact on others as well. Already the discovery of her remains in 1968 had led to the establishment of the Kentucky State Medical Examiners Office.
Then, 30 years later, the discovery of her identity in 1998 led to the creation of a state-based website by the Kentucky Medical Examiners office, called UnidentifiedRemains.net.
My colleagues and I get hundreds of e-mails a day from people searching for their missing loved ones
The websites work by gathering the information on missing and unidentified cases. A review process then begins. Researchers begin combing the web for any shred of missing information in the news media or public databases or websites.
Rules and methods have evolved to make the process work better. Data must be validated for accuracy by communicating with law enforcement authorities, and the Doe Network has a protocol which volunteers must follow to prevent them jeopardising cases or putting themselves in danger.
Case files are in a constant state of review and cross-referenced by members, law enforcement and the public.
The Doe Network alone has helped bring closure to 38 cases of missing or unidentified people. They have also helped gather data to keep thousands of other similar cases in the public eye in the hope of resolution.
Often people involved in using the Internet to help resolve crimes are called amateur sleuths. I think the amateur effort is becoming an actual science. Those of us who seek the technology of the Internet, but not only the Internet, to find resolve in cold cases have found a niche that truly deserves a name. I suggest the term techni-criminologist after which I have named my website, TechniCriminology.info.
My colleagues and I get hundreds of e-mails a day from people searching for their missing loved ones. This is a new age where the ordinary man can step up and make a difference. It doesn't matter your sex, age, race or physical disability.
There are no boundaries to the level of involvement you choose to take - and for those cold cases that have been filed away by hard-pressed law enforcement, a Doe Network volunteer spending hours on a computer in their back room, may be the only chance of keeping a case alive.
Todd Matthews presents Internet Sleuths, a Falling Tree production, on Radio 4 on Tuesday 24 April at 1100BST then for 7 days at Radio 4's Listen again page.