In February, men, women and machines worked closely together sifting and digging dirt from a well in Linden that held gruesome vestiges.
Day after day, week after week, pile after pile, fragments of bones emerged from the ground. Finger joints, skulls and femurs began to build into a mountain of human remains.
But how old were these bones? And, perhaps more important, to whom did they belong?
Now those questions are being answered by criminalists at a state lab in Richmond, Calif., using a blend of art and the latest science.
Huddled over what looks like a sturdy, plastic safe, a criminalist dressed in a white lab coat and plastic gloves fills a box with a steady jet of liquid nitrogen before carefully placing a sealed, clear vial within.
The vial contains a fragment of bone that will be ground into a fine powder.
That powder will then be used at the state's Department of Justice lab to extract a few microscopic samples of DNA.
Those small fragments of genetic material will be crucial in identifying just whose bones the criminalists have. But more importantly, the DNA samples will be used to give some family, somewhere, the peace of mind that their loved has been identified and can be returned to them.
Two sets of remains have already been identified — those of 25-year-old Clements resident Cyndi Vanderheiden and those of 16-year-old Stockton resident Chevelle "Chevy" Wheeler.
But their remains were only a fraction of what is still left to identify.
It may take weeks or even months to complete the exacting process. That can be an agonizing wait for those who wonder whether the remains of their loved one may be among the 1,000-plus bones and bone fragments discovered in the Linden well and on serial killer Wesley Shermantine Jr.'s former San Andreas property in February.
Yet the DNA identification process has become steadily faster and more precise. In less than 30 years, in fact, DNA breakthroughs have revolutionized the way suspects, criminals and victims are identified.
A well-known local case was that of Peter Rose, who was convicted in 1995 of a brutal rape of a 13-year-old Lodi girl. In 2004, he was released from prison after he was proven innocent due to DNA evidence.
DNA is everywhere
DNA profiling was first described by Professor Alec Jeffreys in 1985 at the University of Leicester in England.
He found that certain sections of DNA contained sequences that were repeated over and over. He also found that the number of repeated sections in a sample could differ from individual to individual.
By developing a technique to look at and analyze the length variation of the repeated DNA sequences, Jeffreys created the ability to conduct human identification tests.
His research has been eagerly adapted by law enforcement.
Samples of DNA can come in many shapes and sizes. While most assume DNA just comes from blood, almost anything a person touches can create some sort of DNA sample, according to John Tonkyn, the criminalist supervisor at the Jan Bashinski DNA Laboratory in Richmond.
Tonkyn said criminalists can test any aspect of the body for DNA, though blood is the best source for identifying an individual.
However, should blood not be available, Tonkyn said criminalists use bone and bone fragments, using tools to extract DNA for identification purposes.
Teeth, in particular, are a good source for DNA testing because they are covered in dentin, the hardest substance in the body, which protects the teeth from wear and tear.
Did you know you can use a fingernail and even the collar of your shirt as a source for DNA testing?
Tonkyn said fingernails are actually an adequate DNA source. If sampling options are scarce, lab technicians can scrape skin cells from things like a toothbrush, baseball cap or the collar of a shirt to try and find options for DNA testing if bones or blood are not available.
However, Tonkyn said the elements in which bones or other DNA sampling options are stored are crucial in helping criminalists extract DNA.
Tonkyn said environmental factors such as dampness and even ultraviolet rays from sunlight can deteriorate the quality of bones or tissue.
Fungi growing on remains or bacteria that has somehow made its way into tissue can cloud criminalists' ability to extract a clean sample of DNA for testing and analysis.
"Whether we can or can't get a DNA profile, we have to give it a try," he said. "You can't tell just by looking."
Tools of the trade
Without a picture of a person, how can you identify someone?
That is the daily work of criminalists with the Bureau of Forensic Services. But because things like a camera or a photograph are not useful to identify someone in their line of work, lab technicians use machines and test tubes to paint a DNA picture of a set of unknown remains.
After gently cutting a piece of a bone off for testing, criminalists use something called a freezer mill to pulverize the bone sample into dust.
The freezer mill is a machine that looks somewhat like a plastic safe. It is sturdy and has a keypad on the top that lab technicians use to program the machine to grind the bone.
The machine combines liquid nitrogen with a mill inside the device to conduct the grinding cycle. Liquid nitrogen is extremely cold, around -321 degrees Fahrenheit.
Once the cycle is complete, the ground sample is removed and can then be used for testing.
Another piece of equipment that can be used in DNA testing is the thermal cycler.
The thermal cycler, which looks a bit like an electric weight scale, allows for DNA to be multiplied into thousands and even millions of the same strand. That way, criminalists can better examine a particular strand for specific markers they are hoping to that that will help identify an individual.
Once DNA is extracted and multiplied, the final phase of the analysis begins.
Known as capillary electrophoresis, this process creates something of an oil and water effect — it separates big strands of DNA from smaller, shorter DNA strands.
This allows criminalists to extract a more complete DNA strand for testing, rather than having to try and fill in the blanks with a partial DNA strand.
When criminalists get an ID, how do they know who the person is?
When a person goes missing or when a criminal is put behind bars, cheek swabs are taken by the Department of Justice and sent back to labs where they are documented in the state's DNA Data Bank.
For missing persons, cheek swabs are typically taken from family members.
The bank was established in 1994 and today contains more than 274,000 felon profiles and 9,300 forensic profiles.
Once samples have been collected and catalogued by the bureau, the next step is to match family members to those remains being tested by the bureau.
As DNA results come in and they are preliminarily matched to an individual, ultimately a county's coroner or medical examiner determines if the results confirm someone's identification or not, according to Michelle Gregory, a spokesperson for the California Department of Justice.
In other words, the department makes preliminary matches, and presents its evidence to the county coroner.
Depending on the accuracy and detail of the results, a county coroner substantiates or rejects the remains' identification.
Getting those DNA results is done through a series of tests, according to Tonkyn.
These tests, however, use separate sections of an individual cell.
One test uses the nucleus, the innermost section of the cell, to help look for 16 specific markers that would be unique to that person.
In humans, DNA disparity determines gender, race or susceptibility to certain diseases. People differ from each other by about one-tenth of 1 percent.
It makes the test extremely specific, Tonkyn said.
The other test involves examining the mitochondria, which is a membrane that blankets a cell.
But the issue with that test, according to Tonkyn, is that the test will match that DNA with anyone who may be maternally related to the individual being tested. That means the results are not as specific.
"You could be pairing the sample with dozens of people," Tonkyn said. "Any person who is maternally related to the family carries that DNA. It is a weaker test, statistically speaking."
However, matching DNA was and is crucial to identifying individuals and even exonerating or convicting someone of a crime.
For example, Peter Rose was convicted of the 1995 kidnapping and rape of a 13-year-old Lodi girl. However, Rose maintained that he was innocent.
At the time, semen found on the victim's clothing was not able to be used in DNA analysis to prove whether Rose was innocent.
However, by 2004, DNA testing had advanced, and the same semen was used in an analysis that eventually exonerated Rose.
There is no hard and fast timeline to get results from DNA analysis.
Even though television shows have projected the idea that DNA tests come back in a matter of minutes — known as the "'CSI' effect" — criminalists say that is simply not possible.
"Unfortunately, the 'CSI' shows do not do justice to the hard work of these criminalists," Gregory said. "Typically the process of DNA analysis/extraction can take anywhere from one week to 30 days, but this is not a timeframe etched in stone either. ..."
Bones from the dig in Linden that have been sent to the department's lab in Richmond, for example, were found nearly a month ago.
And while those remains are labeled a "rush case," Tonkyn said the length of time for getting results on DNA tests depends on how much damage there is to the original sample.
A relatively pristine sample for DNA testing, like a clean bone or a blood sample untainted by dirt or debris, can allow criminalists to get a report out to family members within a week for the nuclear DNA test — the test that is considered to be best for identification purposes.
But if criminalists have to repeat steps throughout the identification process because they could not get enough DNA during the first round of testing, or if they have to use the mitochondrial DNA test, getting results can take longer, Tonkyn said.
Also, because criminalists often juggle multiple cases, or if there are no direct family members to provide comparable DNA samples, results could take even longer.
For families, the wait can be agonizing.
For example, John and Terri Vanderheiden were informed on Feb. 8 that a partial skull and a few bone fragments had been found on Shermantine's former San Andreas property.
On Feb. 11, through dental forensic analysis by a forensic odontologist, there was a preliminary determination that the skull belonged to their daughter.
On Feb. 21, the identification of their daughter's remains were confirmed through DNA testing and analysis conducted by the Department of Justice.
The 14-year wait to finally find their daughter was brutal, the Vanderheidens said.
In an interview with Anderson Cooper last week, despite knowing that their daughter's remains have been identified, Terri Vanderheiden admitted it was still hard to accept.
"I still leave the porch light on at night," she said. "(I am) hoping there was a mistake and that she will be walking down the road."
Criminalists are moving steadily through remains from Loren Herzog and Wesley Shermantine Jr.'s killing spree that spanned nearly two decades. Herzog committed suicide in January.
Shermantine, now on death row in San Quentin, has correctly led investigators to two separate burial sites so far.
He says there are still more remains to be found.
But the number of people who fell victim to Shermantine and Herzog remains a mystery, as does their identity.
There is speculation as to who has been found so far. Perhaps a missing pregnant woman from Modesto who disappeared in the 1990s. Or maybe a 9-year-old Hayward girl who vanished in 1988. Even a young Lodi woman whom no one has seen since 1981.
Were these the remains that were found in Linden weeks ago?
The answers may come from a lab in Richmond, where the work continues.
Contact reporter Katie Nelson at firstname.lastname@example.org.