More than 10,000 people participated in a run through downtown Boston in tribute to first responders and law enforcement officers who lost their lives in the line of duty.
Fallen Yarmouth police officer Sean Gannon was among those honored Sunday. Gannon was killed in line of duty in April.
Gannon's police car took a last drive on Sunday's course.
Yarmouth Deputy Police Chief Steven Xiarhos ran in memory of Sean Gannon as well as his own son Nicholas, a Marine who was killed in Afghanistan in 2009.
"It's very emotional to come back here and run for Nicholas," Xiarhos said.
Xiarhos participated in the run with Nicholas in 2006, the first run the pair participated in together before his son headed to the Marine Corps.
Xiarhos said officers in the Yarmouth Police Department are continuing to heal following the loss of Gannon.
"We went through shock, sadness, we have a lot of anger. This shouldn't have happened." Xiarhos said. "Now we're using Sean's murder and the shooting of our dog Nero to change the system, and we will."
Now in its fourteenth year, the event attracted runners from as far as Los Angeles to participate and show their support.