Spencer the golden retriever has been supporting runners in the Boston Marathon for four years. He went viral last year after sitting through the rainy marathon holding a "Boston Strong" flag.

Spencer, named the official dog of the Boston ... Known for his signature two Boston Strong flags that he’d hold in his mouth, the trained therapy dog stood across the street from where the ...

Exhibited this year just minutes from the race’s starting line, at the Hopkinton Center for the Arts, Celebrating Spencer shows the official marathon dog holding a Boston Strong banner — a ...