GLENWOOD SPRINGS, Colo. -- As the Office of Special Investigations commemorates the eighth anniversary of one of its darkest days, Dec. 21, the 2,200-mile hike of Special Agent (Ret.) Greg Pfeiffer reemerges amid the season of giving.
In the wake of the COVID-19 pandemic, Pfeiffer trekked across the Appalachian Trail, stretching from Georgia to Maine, with each step dedicated to every one of OSI's fallen heroes in a journey that transcended physical boundaries.
Turning his lifelong aspiration into a tangible cause, the retired senior master sergeant initiated a digital campaign that raised over $20,000 for the families of fallen servicemembers. Through video blogs, he went beyond documenting his journey; his videos served as a platform to enlighten thousands about the lives and lasting legacies of OSI's bravest, sharing their tales of heroism and sacrifice with every post.
"This hike is not about my personal story,” Pfeiffer said. “This is my dedication to OSI’s fallen, a pledge to keep their sacrifices and legacies in our collective consciousness.”
Special Agent (Ret.) Terry Krebs, a fellow hiker and long-time colleague of Pfeiffer, views this dedication as a true reflection of Pfeiffer's character.
"Greg perfectly embodies what OSI represents," Krebs said. "He is a quiet professional who completed a journey less about personal glory and more about honoring to the commitment and sacrifices of our fallen colleagues, symbolizing the ethos of our entire organization."
On the trail
While Pfeiffer emphasized that his journey wasn't about personal glory, finishing the AT in one go is a feat few accomplish. According to the Appalachian Trail Conservancy, thousands set out each year, with only about a quarter reaching the trail's end.
Aware of these odds, Pfeiffer started his hike in early 2021, aligning with the influx of hikers and ideal spring conditions. Amid the early throngs, it was Pfeiffer's pack, a mosaic of names and stories, that became a focal point, Krebs said, drawing interest and dialogue among the outdoor community, who dubbed him ‘Captain America.’
Pfeiffer's 'Captain America' trail name wasn't just about the names adorning his backpack. It also came from his USA flag-themed socks, as well as a large, patriotic tattoo noticed at a hostel and the OSI insignia on much of his clothing.
Before embarking on his journey near Springer Mountain in Georgia's section of the Blue Ridge Mountains, Pfeiffer received a heartfelt send-off from retired Col. Rick Law, a 28-year OSI veteran. Living roughly 10 miles away, Law, a former OSI Region 1 commander, felt compelled to be there despite retiring from OSI decades prior and never having met Pfeiffer.
Law, pulled by the sense of community inherent in OSI, explained, "When you're a part of OSI, you're part of a family," he said, adding with a laugh, “whether you like it or not.”
On his way to meet Pfeiffer, Law stopped in Gilmer County, celebrated as the ‘Apple Capital of Georgia,’ to pick up fresh-baked pies. This gesture was for Pfeiffer and his brother, who not only joined him at the trailhead, but later rejoined him for the journey's conclusion.
“When we arrived [at Springer Mountain], I helped them with their gear and gave them the apple pies,” Law said. “Before parting ways, we shared a moment of prayer. We prayed for peace, safety from injuries and for their journey to be purposeful and successful.”
Following Law's send-off, Pfeiffer's journey really took shape. The Appalachian Trail introduced him to a cast of memorable characters. Notably Mark Ryan, a North Carolina business owner, known in the trail community as 'Rapture.’
In a twist of fate, Pfeiffer discovered that both he and Rapture embarked on their respective journeys from Springer Mountain on the same day, yet their paths intertwined later in Franklin, North Carolina.
Pfeiffer spoke of Rapture not just as a close friend, but an ally in his fundraising efforts. Together, they forged a strong bond over 1,800 miles, he said, a testament to the sense of community that defines the AT.
"[Rapture and I] were in sync,” he said. “We even summited on the same day. We had similar hiking routines but didn't necessarily walk every step together."
Although Pfeiffer and Rapture usually took different routes on their daily hikes, their routines aligned each day; they started their mornings around the same time and reconvened at the same spot by nightfall. This synchronization offered a unique form of mutual support, he said.
Honoring the fallen
Deep into his hike, Pfeiffer found himself in Pennsylvania, the native state of fallen Special Agent David Wieger. In a video blog filmed within his tent, Pfeiffer took a moment to pay tribute to Wieger, exploring the agent's impactful life and roles within OSI.
As he spoke, Pfeiffer's tone grew somber, turning to the events of Nov. 1, 2007, in Balad Air Base, Iraq, the day that brought the loss of Wieger along with Special Agents Thomas Crowell and Nathan Schuldheiss. He honored their bravery and the ultimate sacrifice they made, recounting the tragic incident with an improvised explosive device that led to their deaths.
In earlier uploads, Pfeiffer also dedicated videos to both Crowell and Schuldheiss, methodically honoring the stories and memories of each in his series of tributes.
“We were honored that he did that -- not only for David -- but for all of the fallen,” said Lori Wieger, David’s mother. “I know it means so much to all the families, like it means so much to us.”
Finding his trail legs
As the weeks unfolded into months, Pfeiffer refined his approach to the hike, turning it into an efficient routine. His stops were brief and purposeful: to replenish his food supplies, clean the minimal clothing he had and recharge just long enough for the next leg of his journey.
“At any point he could have quit,” Krebs said. “He could have hopped on a plane and been home in a few hours -- but he didn’t.”
Each trail town along the way, from Vernon, New Jersey, to Hanover, New Hampshire, posed the recurring question: to push forward or go home. Even for Pfeiffer, the AT's 'Captain America,' the struggle was often very real.
“My approach was taking it three to five days at a time,” he said. “Just make it to the next trail town.”
Pfeiffer and his wife, Jessica, a retired master sergeant, were well-prepared for the long hike, she said, as their military careers having seasoned them for times apart.
“Given both of our military backgrounds, I think it was easy for both of us to be apart for those six months,” Jessica said. “I had a great support system of neighbors and some of Greg’s former colleagues who consistently made sure everything was going well.”
Jessica even joined her husband briefly on his journey, hiking a 30-mile stretch of the trail with him. This experience, she said, gave her a deep respect for distance hikers. "You really need to be mentally and physically prepared for such an endeavor," she added.
"Nothing quite prepares you for the daily 20 to 30-mile hike," Greg said. "You just have to get out there and do it. Training in the gym or on a Stairmaster helps, but true physical readiness comes on the trail as you develop your 'trail legs' over weeks."
But for Pfeiffer, it was the names on his backpack that were the strongest motivators. "Seeing those names meant giving up was never an option," he said, adding that his commitment to the hike was more than a public dedication for awareness; it was deeply personal.
"OSI's fallen were walking that trail alongside him," Law said. “I have no doubt of it, and I’m sure he knew it, too.”
Krebs, who serves as a liaison between OSI and the families of the fallen, closely followed Pfeiffer's progress online. "I kept the families informed about what he was doing," he said. "Greg's efforts were a testament to OSI's commitment to never forget its fallen heroes.”
Remembering OSI’s ‘darkest day’
By June 2021, after trekking 1,500 miles, Pfeiffer reached Kent, Connecticut, just a few hundred miles from the finish line in Maine.
Surrounded by the backdrop of trees and the distant melody of birds, he filmed another video blog. This one dedicated to Staff Sgt. Louis Bonacasa, one of OSI's fallen heroes and native of East Patchogue, New York, around 125 miles from where Pfeiffer stood.
Speaking into the camera, Pfeiffer told the story of six OSI members, who on Dec. 21, 2015, near Bagram Airfield, Afghanistan, were killed during an outside-the-wire mission, he said into the camera, his voice competing with the natural sounds of the surrounding wilderness.
That day would later be called “OSI’s darkest day” by retired Brig. Gen. Keith Givens OSI commander at the time, he said.
During the video, Pfeiffer also shared a personal connection to the fallen agents, noting his own deployment with the same unit in Afghanistan years earlier. This connection, he felt, brought him closer to understanding the types of missions they undertook.
“It feels like it happened just yesterday,” he continued, displaying a wristband to the camera with their names inscribed. “Just like how people remember where they were on 9-11, I remember the moment I heard about the loss of six of our own.”
In the video updates that followed, Pfeiffer honored other members from that fateful day. He continued with Tech. Sgt. Joseph Lemm, another Security Forces Defender, who along with Bonacasa, was later posthumously named Honorary OSI Special Agents.
His video tributes continued as he moved north, discussing the lives and service of the other four agents killed that day, including Special Agents Adrianna Vorderbruggen, Michael Cinco, Peter Taub and Chester McBride.
This visibility transformed the retired senior noncommissioned officer into an informal ambassador for OSI, Krebs said, adding it introduced the agency's greatest heroes to those possibly unfamiliar with its legacy.
‘Maine or bust’
With countless miles behind him, Pfeiffer had set his sights on Maine, and more precisely, Mount Katahdin – the final checkpoint of his journey.
"Today is July 17, 2021, and it's Mount Katahdin Summit Day," he said into his camera, his face a blend of excitement and weariness.
As Pfeiffer crossed the finish line at Mount Katahdin, he was not alone; Rapture and his brother were by his side. Throughout his journey, he found camaraderie and support all around, from Law driving him to the trailhead at the start, to seeing former OSI colleagues like retired Chief Master Sgt. Mike Tanguay, who provided essential supplies and food along the way, or Special Agent Andrew Navia, a fixture in many of his videos.
But for Pfeiffer, the most present were the names of fallen OSI agents he carried on his backpack, he said. Even as he achieved his lifelong goal, it was their names he wanted to highlight and remember.
“When OSI says we will not forget, they don’t,” Lori Wieger said, “They haven’t forgotten David, and it's been 16 years. They are amazing, and we love every one of them.”
Life after AT
After completing his hike, Pfeiffer allocated the $20,000 raised to a nonprofit building a vacation home in Maine for the families of fallen servicemembers, a project designed as a comforting retreat.
A key figure in those fundraising efforts, he said, was his mother. Her efforts rallied the Loveland, Colorado, community they’re from in support of her son's cause. His mom even accompanied him on a segment of the trail in New York, where she braved a near-fainting incident and a close call with a rattlesnake.
The year also brought sorrow. Rapture, an Army veteran and Pfeiffer's loyal trail companion, died Dec. 16, 2021, in Hendersonville, South Carolina. He was 57.
"Rapture's death taught me a crucial lesson about making the most of every day,” he said. “I think about him daily and how much he loved every moment on that trail."
Teaching tomorrow’s leaders
In the year and a half following his Appalachian Trail hike, Pfeiffer continues to live each day to the fullest, a lesson ingrained in him by Rapture.
Now, he channels his energy into being a Junior Reserve Officer Training instructor at Glenwood Springs High School, home of the Demons, in his home state of Colorado. There, he has doubled the JROTC program’s size, with even more cadets joining next semester.
“He's an amazing example of somebody who should be teaching leadership to our future leaders,” Law said. “With his combat experience and what he accomplished on the Appalachian Trail, they're going to look at him as someone to look up to.”
But Greg's focus remains on serving others. "I want to do my part," he said, aiming to influence the next generation of leaders. "If I connect with even one cadet, it’s worth it."
Embracing his new life challenges, Greg has adopted a familiar approach: take things one trail town at a time.