Monday marks seven years since Chattanooga Police Sgt. Tim Chapin was shot and killed in the line of duty. 

Sgt. Chapin was killed by an armed robber in a shootout behind a Brainerd Road pawn shop.

The Chattanooga Police Department posted a tribute to Sgt. Chapin on Facebook that said:

"'A hero is someone who has given his or her life to something bigger than oneself.'-Joseph Campbell 

RIP Sergent Tim Chapin. Your service, leadership and sacrifice will not be forgotten. EOW: April 2, 2011."

Other law enforcement agencies across the Tennessee Valley are also remembering Sgt. Chapin on social media.