15 years ago, an America flag hoisted at Ground Zero just hours after the September 11 terror attacks went missing.

Soon after its disappearance, a nationwide search for the iconic piece of American history was on.

In 2014, at fire station in Everett, Washington, a man named “Brian” dropped off a plastic bag. Inside it- an American flag.

He told firefighters he was a Marine and was given the flag as a token of appreciation for his service by the National Oceanic and Atmospheric Administration (NOAA). According to Brian, it was originally given to NOAA by a 9/11 widow. However, after watching a show on History Channel about the missing flag, Brian decided it was time for it to be returned to its rightful owners: The American people.

Firefighters then turned the flag over to police, and that’s where Washington State Patrol Forensic Scientist Bill Schneck comes in.

Mr. Schneck spent months running everything from chemical to photo analyses. In the end, his hard work resulted in a monumental success. His team was able to positively ID the missing “Ground Zero Flag” and immediately send it back to its home in New York. He said it was the “most patriotic thing I’ve ever done.”

Over the weekend, Mr. Schneck traveled to NYC for the unveiling of the flag at the 9/11 Museum. Upon arrival, he remembered an old photograph of the Millennium Hilton Hotel taken just weeks after the attacks by a WSP employee who was volunteering at the time. He snapped a photo— and the difference 15 years makes is extraordinary.

At the flag’s welcoming home ceremony, Mr. Schneck said he had never felt more proud to be an American. Adding he was honored and shocked to see the Washington State Patrol Crime Lab mentioned in the display case. “I was saddened to remember the extreme loss of life that took place 15 years ago; but in that darkness it was deeply moving to see how much the flag meant to New York and America in their healing process,” Mr. Schneck said. Photos taken by Mr. Schneck are below.