Dried blood and brain matter cover the once-crisp white dress shirt. The gray wool suit coat and pants are stained with blood drops.
The thin, blue necktie was nicked by a fast-moving bullet.
The clothing worn by President Kennedy on the day of his assassination 50 years ago Friday is preserved at the National Archives and Records Administration facility in College Park, Md.
Dr. Peter Cummings, a forensic neuropathologist from Beverly, had a front-row seat to history when he examined the former president’s clothing, along with X-rays and autopsy photographs, for “Cold Case JFK,’’ a special episode of the PBS science show “Nova.”
“The gravity of the situation just really hit me,” Cummings, 42, said of his experience. “The president’s suit, right there in front of me — I wasn’t just walking through a museum, seeing a display. I was participating in history.”
“Nova’’ arranged for researchers to apply modern forensic science and ballistic testing to try to answer questions that still fuel conspiracy theories a half-century after that fateful day — Nov. 22, 1963 — in Dallas.
From which direction was the fatal shot fired? Where did it strike the president?
“It was a single gunshot wound to the back of his head,” Cummings said without hesitation. “It was right where the autopsy doctors said it had happened.”
The president’s clothes provided valuable clues.
“I was mostly interested in the shirt and tie,” said Cummings, who specializes in gunshot wounds to the head. “I wanted to see the location of a hole in the shirt, to see if it was consistent with a gunshot wound. It was.”
Cummings made his conclusions after spending eight months poring over thousands of pages of hearing transcripts, medical testimony, and other materials available online from the national archives.
In September, he traveled to Maryland to examine the slain president’s clothing and original autopsy materials. Access is limited to federal government officials and qualified researchers, who must be approved by the Kennedy family.
The restriction aims to “prevent the undignified or sensational use of the materials or any other use which would . . . dishonor the memory of the late president, or cause unnecessary grief or suffering to members of his family,” the National Archives said in a statement to the Globe.
Cummings had a strict limit on how long he would be able to examine the materials, he said.
‘Once I saw those photographs, it became very clear what had happened to President Kennedy.’
“When the door closed, I knew I only had two hours. I just sat down and looked at the photographs,” he said. “I treated it like any other gunshot wound case.”
The president’s clothing has been kept in a deep cold storage, Cummings said.
“It looks pristine. I could not believe it was 50 years old. It’s so well-preserved, “ he said.
With the X-rays and photos spread before him on a table, Cummings wrote notes about fracture patterns, lacerations, bruising, and other injuries to the skull.
“The quality is fantastic. Once I saw those photographs, it became very clear what had happened to President Kennedy . . . It was a single gunshot wound to the back of the head. Based on the fracture pattern, we can say there was no shot from the side or the front.”
But was Lee Harvey Oswald the gunman?
“Whether or not Oswald pulled the trigger, I don’t know,” Cummings said of the man who investigators say shot the president from a sixth-floor window of the Texas School Book Depository. “But I know that it [the fatal shot] came from above and behind. That’s what I would have told the police.”
“Cold Case JFK” ended a week of being shown nationally on PBS stations Wednesday, and the episode is still available online.
“Thousands of people have made up theories about the assassination, and most of them are not experienced or qualified,” said Rush DeNooyer, director of the TV program. “We thought, ‘It’s been 50 years. Let’s see what some real, qualified science can tell us about what happened.’ ”
For the show, Cummings teamed up with James Pokines, a forensic anthropologist at the Boston University School of Medicine, and Greg Mahoney, a forensic artist with the Boston Police Department.
They created a 3-D model of Kennedy’s skull to help them re-create his head wound.
“We tried to take the fragments of his skull and put them back anatomically, where they belong,” Cummings said.
Mahoney used a bust of the late president and his hat size, 6⅞ inches. “We were able to approximate the size and shape of Kennedy’s skull,” Mahoney said. “We got it as close as we could to the actual size.”
Cummings, who works as a forensic neuropathologist for the state medical examiner’s office, also maintains a private consulting practice. He is frequently called as an expert witness in court cases around the country.
He recently agreed to consult for the Irish Innocence Project in Dublin, which is part of a global network that uses DNA to examine cases where wrongful conviction is suspected.
“I think its important for everybody to have access to good science,” said Cummings. “I think it’s very important for justice to work. My job is to look at the science, interpret it, and then convey that information to a jury. They make up their mind about what’s best.”
Cummings, who grew up in Millinocket, Maine, earned a bachelor’s degree in zoology from the University of Maine, a master’s degree in pathology at Dalhousie University in Halifax, Nova Scotia, and a medical degree from the Royal College of Surgeons in Dublin.
He fell in love with forensic pathology after enrolling at Dalhousie in 1997, Cummings said.
A year later, a Swissair jetliner crashed off the coast of Nova Scotia, killing all 229 people on board. A chance meeting with the medical examiner led Cummings to volunteer for two years, collecting DNA to identify victims.
“From the moment they unzipped the first body bag, I said, ‘There is nothing else in the world I can do with my life.’ It was the fascination of trying to reunite someone’s remains,” Cummings said.
He moved to Massachusetts in 2008 after landing a fellowship at the state Office of the Chief Medical Examiner. He was hired as a staff pathologist the next year, he said.
Cummings and his wife, Sarah Parker, an economist, settled in Marblehead, where she had lived as a child. The couple last month moved to Beverly, where their son, Fionn, 7, attends school.
Cummings’ interest in medical investigations is long and deep. In Millinocket, a small town 70-odd miles north of Bangor, he grew up playing with chemistry sets, and earning bragging rights as the best science student in school.
He recalls watching a PBS special on President Kennedy’s assassination with his mother when he was 10 or 11.
The crackle of gunfire, and the sight of the fatally wounded president, shocked the precocious boy. He was puzzled to learn that there could be controversy over the assassination.
“I think the narrator said, ‘Science can’t answer these questions.’ I remember thinking, “What do you mean? Science tells me everything,’ ” he said.
Over time, as he learned more about forensics and medicine, Cummings sometimes wondered about the lingering mystery of Kennedy’s death. But he never spent any time on it until he was asked to participate in the “Nova’’ program. He was not paid for his work on the show, Cummings said.
He spent much of the last year immersed in the mystery of the most famous murder in modern history.
“I spent nights, weekends, even reading on the train about it,” he said. “Every free moment I had, I was reading about Kennedy.”
Like his father, Fionn Cummings had his own questions about JFK. One day, as his doctor-dad sat surrounded by model skulls, copies of autopsy photos, and pages of medical testimony, Fionn posed a question: “If President Kennedy has been dead for 50 years, why does it matter now?”
His father paused before answering: “Because the truth always matters, no matter how long it’s been.”Kathy McCabe can be reached at katherine.mccabe@ globe.com. Follow her on Twitter @GlobeKMcCabe.