DOVER AIR FORCE BASE, Delaware — The last thing Charles McDaniel remembers of his father is a fleeting, joyful moment: running out of the house to greet his soldier dad coming home from work and he “picking me up and doing what dads do, bouncing me around a little bit.”

Charles was 3. His brother Larry was 2. Their dad, Master Sgt. Charles H. McDaniel, a medic in the U.S. Army, left for the Korean War, and went missing in the Battle of Unsan on Nov. 2, 1950.

Now 71 and 70, they received their dad’s dog tag earlier this year as part of President Donald Trump’s outreach to North Korea, which produced 55 cases of human remains and may produce more if the two sides keep talking.

On Thursday, the McDaniels received closure when President Trump tweeted that McDaniel’s remains had been identified, along with those of Army Pfc. William H. Jones, 19, of Nash County, North Carolina.

Larry and Charles are among the fortunate ones. Other families may have to wait up to a decade to hear whether the remains of loved ones have been recovered. They expressed this concern most recently at an annual gathering near the Pentagon to officials from the Defense POW/MIA Accounting Agency and the Armed Forces Medical Examiner System.

Questions included, “Why not outsource the testing to other U.S. labs to speed the process?”

The simple answer? The officials said few labs can currently match the forensic expertise resident at the POW/MIA’s lab in Hawaii, where the remains are sent, and they definitely can’t match the speed and complex DNA analysis under way at the lab based in Dover—taking tiny fragments of DNA invisible even to microscopes, copying them and knitting them back together to come up with strands that match surviving relatives.

If you’ve ever watched NCIS, the characters Dr. Donald “Ducky” Mallard and lab tech extraordinaire Abby Sciuto, the lab in Dover is where they’d actually work. It’s the only federal medical examiner system serving the FBI, Justice Department and NTSB, as well as the Pentagon.

At the POW/MIA event, top officials from the lab explained patiently and in detail why they can accomplish identifications faster than any other lab else, depending on the condition of the bones, thanks to new advances rolled out in 2016 borrowed from medical testing of DNA for the living.

The anguish of those family members, and the struggle to identify dead soldiers from Vietnam, North Korea and earlier wars, also drove the military to construct a repository at Dover of DNA samples from every military member since the early 1990s.

Next to the high-tech DNA labs is a temperature-controlled warehouse with floor-to-ceiling shelves on motorized wheels. The shelves hold nearly 8 million carefully catalogued cards with drops of blood that most troops don’t even remember giving in their first days of service—cards that continue to help identify fallen soldiers from today’s wars, or in rare cases, help solve crimes in which a service member is a victim or a suspect.

There are more than 82,000 Americans still missing from World War II, the Korean War, the Vietnam War, the Cold War, and the Gulf Wars, as well as other conflicts. Three-quarters went missing in the Indo-Pacific, and more than half of the total were lost at sea.

“ “If we have dental remains, that’s a slam dunk. That’s done in months. If we have DNA that’s been degraded, or treated, then it’s a matter of years.” ” — Kelly McKeague, director of Defense POW/MIA Accounting Agency,

The recently returned remains from North Korea are being examined at the POW/MIA lab in Hawaii, where specialists including forensic scientists compare teeth against dental records, or chest clavicles against the X-rays taken in the 1950s to make sure troops were clear of tuberculosis. DNA samples are harvested in Hawaii, and sent to the Dover lab.

“If we have dental remains, that’s a slam dunk. That’s done in months,” Kelly McKeague, director of Defense POW/MIA Accounting Agency, told The Daily Beast. Same with a clavicle, he said. “If we have DNA that’s been degraded, or treated, then it’s a matter of years.”

DNA degrades when exposed to acidic soil and the elements, or perhaps exposed to some sort of chemical such as formaldehyde.

That’s where the lab in Dover comes in. It’s the only accredited forensic laboratory in the country that can recreate an entire genome from the mitochondrial DNA of the remains, according to spokeswoman Jennifer Vallee.

A chunk of stone left from the 9/11 attack on the Pentagon is embedded outside the unassuming building on Dover Air Force Base, where troops are transported for autopsy. The team here was tasked with identifying those who died inside the Pentagon, and on the plane that flew into it—as well as those on the plane that crashed in Pennsylvania.

The building also houses the blood repository, and the high-tech DNA lab that works to identify those missing in action, or anyone lost on federal land.

“Our job is to take care of the war-fighter in their final hour,” said the lab’s director Col. Louis Finelli. It's also helped keep service members safer on the battlefield, and “to keep the government honest—to make sure they are doing nothing nefarious,” by checking the dead against the official reports of how they supposedly died, he said.

Finelli has spent hours briefing family members of the fallen on every aspect of an autopsy, able to explain to them why perhaps a fellow trooper was insisting that a soldier who died was still breathing, and perhaps could have been saved.

“There’s something called agonal breaths,” he explained. “The chest is moving, but they’re not breathing with any purpose because the injuries are too severe to survive... and they’re not conscious.” But those last breaths can mislead other soldiers who may tell family members that the man or woman “was still breathing when they last saw them” so perhaps could have been saved.

Finelli’s toughest week on the job was in 2004 during the two Battles of Fallujah in Iraq. “I vividly remember when I didn’t autopsy anyone older than 19 years old for over a week,” he said.

For families who are resistant to having their loved one autopsied, he tries to explain how the procedure has revealed what is and isn’t working on the battlefield. Medical examiners were able to teach medics that the needles they were using to release fluid from an injured soldier’s lungs were too short for heavily muscled troops. Troops were dying because the needles weren’t penetrating their lungs—so now medics automatically reach for the longer needles in medical kits.

The medical examiners were also able to overturn the old lore that medics should at times hold off on using tourniquets on badly injured limbs, because that might starve the limb of oxygen and kill it. The doctors were able to show that skipping the use of a tourniquet was actually killing troops, meaning that it didn’t matter if the limb was saved.

Autopsies also brought accountability, Finelli said. He was based at the lab when its teams found suspicious injuries on dead detainees from the U.S. military detention facility at Abu Ghraib.

And it was the autopsy of all-pro football-player-turned-U.S.-Army Ranger Cpl. Pat Tillman that helped reveal he died from friendly fire, helping to discredit initial reports that he was shot by the enemy. “It didn’t look right from the beginning,” Finelli said.

It’s in the science of DNA where the lab is at the cutting edge. Most labs focus on nuclear DNA. (Recall from biology lessons, a cell has a nucleus, and small “organelles” including mitochondria.) Decades of exposure often destroy the nucleus and with it, the nuclear DNA, but there can still be small fragments of the much tinier mitochondrial DNA in remains.

At Dover, they’ve borrowed next-generation DNA sequencing technology from the medical diagnostic wold, and perfected a way to filter out the different mitochondrial DNA strands, and rebuild them into something they can compare with the DNA from family members, to help the POW/MIA agency make an identification. They test for several DNA types and variations, but they lead with mitochondria.

“It’s almost like making multiple copies of small segments of your DNA and sequencing it hundreds, thousands, millions of times,” said DNA analyst Jennifer Higginbotham of the technology, which came on line at Dover in 2016.

The advances mean they are able to identify samples that had been shelved as inconclusive or thought impossible to read, like roughly 800 troops from the Korean war buried in the Punch Bowl in Hawaii. Back in the 1950s, troops in Korea embalmed the unidentified troops to preserve them for the journey home—not realizing that they were destroying much of the DNA in the process. Embalming involves soaking the bodies in formaldehyde, and then drying them for transport by baking them at 300 degrees Fahrenheit.

Before mitochondrial DNA advances, there’d been no way to identify those who’d been embalmed, but since 2016, the Dover lab has been working through samples to help put names to them.

The DNA advances helped agencies reach the congressionally mandated rate of 200 identifications a year last year, for the first time.

“We’re running 700 samples a month, to get to 3,000 analyses per year, to get to 200 identifications,” explained Dr. Timothy McMahon, the director of DNA operations.

The POW/MIA agency sent Dover one set of remains from a burial site in Korea, thinking there were seven people because of the types of bones present. “They took 99 cuttings of different bones, and we generated 31 mitochondrial strands, meaning up to 31 individuals are in there,” McMahon said.

Why hasn’t this happened faster? Because DNA science is relatively young, and it’s still evolving.

Watson and Crick revealed DNA to the world in 1953, just as the North Korean armistice was signed. DNA was first able to be sequenced in 1976, at the end of the Vietnam war. And in 1987, researchers figured out how to copy DNA.

In 1988, DNA was used for the first time in a criminal case to convict accused killer Colin Pitchfork in Britain.

Then in 1990, Defense Department scientists first used mitochondrial DNA for the very first time, to identify a missing soldier from Vietnam, McMahon said. During Operation Desert Storm in 1990, a number of service members couldn’t be identified. That drove Congress to mandate the blood draws and repository.

Now, roughly 250,000 DNA cards arrive each year, in a sealed plastic bag usually collected when a troop reports to boot camp.

Move over, Indiana Jones & the Lost Ark

The index-sized cards, reminiscent of an old library card file, have two thumb-sized drops of blood next to the service member’s name, date of birth, social security number and military branch. The cards are catalogued and sealed in a foil-lined plastic pouch to keep the blood drops from oxidizing, and the DNA in the sample breaking down.

“We use a food-saver like system to vacuum-suck out all of the air and heat seal it, so it’s in an airtight environment,” McMahon explained.

The blood samples are kept on file for 50 years, though a service member who has left the service—and who can’t be called back to duty—can request the sample be destroyed sooner. Most don’t.

In rare cases of an investigation involving federal crimes—and only as mandated by a federal judge—the lab will share those results. It’s done on a case by case basis.

McMahon described one of the handful of times a card was shared with law enforcement. A wife and her serviceman lover plotted the murder of her husband, dismembering him and hiding the body parts.

Years later, the guilt-plagued wife tried to confess to the killing, but police told her they could do nothing to acknowledge the man’s death without a body. So she provided the still-bloodied murder weapon, and the lab helped the police match the blood on it to the serviceman’s card on file, and justice was served, McMahon said.

Holding out hope

When the McDaniel brothers spoke about their father, just after getting the dog tag back, they braced for the possibility it could take months or years to see if their dad’s remains were also in the cases from North Korea. They never expected to get an answer so fast, which came thanks to the Dover lab.

“We are still working through the sense of relief and grief at the same time,” Charles McDaniel emailed from Hawaii, where he and his brother were taking part in the National Day of Remembrance for POW/MIAs with other families, at the National Cemetery of the Pacific.

Just down the hall from where teams are combing through fragments of DNA, a team of clerical staff is going through stacks of newly arrived blood cards for the repository, painstakingly hand-snipping each plastic-wrapped card open—all part of a process to try to end the painful years of waiting and uncertainty families like the McDaniels have endured.

One of the workers has a small handwritten sign above the computer she uses to check each card against a database. It says, “Slowly but surely.”

She’s personally helped catalogue 5 million out of the nearly 8 million blood cards. When a card is accessed to help identify a military member, a small snippet of red evidence tape is affixed to the top.

The evidence tape visible on cards on almost every row shows how she and her team have helped thousands of families find some measure of peace.

Editor’s Note: This story has been updated to add reaction from Charles McDaniel to the identification of his father's remains.