Mystery Solved! 100-Year-Old Dog Tag Returns Home to World War I Veteran's Grandson

"He had this around his neck during these battles, and here it comes back to me, 100 years later," 66-year-old Joseph M. Hughes said.

A Massachusetts man received a touching memento from the past when the lost dog tag of his World War I veteran grandfather arrived on his doorstep, exactly 100 years after it was issued.

Read: Man Seeks Owner of Abandoned Trunk Containing Love Letters and Photos from WWII

"[It's] unbelievable," said U.S. Navy veteran Joseph M. Hughes, 66, when a police officer showed up one afternoon with his grandfather's dog tag in hand. "He had this around his neck during these battles, and here it comes back to me, 100 years later."

The Randolph Police Department told InsideEdition.com that the dog tag was turned in after a man discovered it lying on the side of the road.

They then did some research, and discovered the dog tag belonged to Joseph E. Hughes, who was drafted into the Army in 1916, when he was just 18 years old.

The police department then put out an appeal on Facebook, to track down the descendants of the dog tag. Eventually, through social media and the input of the Fort Devens Museum, they discovered a man living in Walpole by the same name.

Hughes, the grandson of the WWI veteran, told InsideEdition.com he was shocked to see officers from a town 30 minutes away show up at his doorstep.

Though it remains a mystery how the artifact wound up so far away, Hughes said he couldn't be more thrilled to discover a side of his grandfather that he never knew.

"He was the type of fellow who didn't say too much when I was young," Hughes recalled of his grandfather, who died when he was a boy. "He'd be sitting in his chair, watching the Red Sox game. He'd let out a roar, that's the type of guy he was. Not too much talk in between."

Read: Mystery Solved! Meet the Woman Who Wrote 27-Year-Old Message in Bottle Found on Beach

But Hughes was fascinated to learn of the battles he fought in France, and the injuries he sustained during the war. He was also surprised to find out that his grandfather, who was one of nine children, had a twin sister.

"I definitely feel like it connects me to a period of time that I remember growing up, but not knowing," he said. "It's a lot of family history I can pass on to my daughter and her children."

Watch: America's Oldest Working Teacher Nicknamed 'Granny' Celebrates Turning 102