Byron White, 17, was taken into custody after Seattle Police got information about the suspect's whereabouts.
A Seattle Police source said White shot and killed David Peterson, 54, nearly a week ago near the Fred Meyer in Greenwood.
"I hope they caught the right guy and I hope everybody can start feeling a little safer in the neighborhood," said Patrick Schowey who works at MudBay and was inside the store during the shooting.
"It's been kind of eery, kind of scary. People have been kind of on edge. It's been kind of a breath of fresh air today since we heard the guy being captured," said Schowey.
The victim was on his nightly walk when he was robbed of his cell phone and murdered.
"(I was) just walking out the doors of the School of Rock and I got about halfway through the street and I heard the shot and my first reaction was I thought it was a firecracker," said Carl Jermain who quickly learned it was more serious than a prank.
Jermain saw the suspect running away then noticed the victim's body lying on the sidewalk. Jermain returned to the School of Rock and his co-worker called 911.
"It's been a tough week. I think we're all dealing with it the best we can," said Jermain.
On Friday, detectives served a search warrant at a home on 4th Avenue NW in connection with the case. They removed items from the home but are not saying what they found.
Police said there are no suspects outstanding in the case. Many are shocked the person now accused of murder is so young.
"They're not smart enough to understand that whenever something like that happens to them, that's their whole life - just gone," said Schowey.