Deputies responded to an emergency call at Pawn X-Change in the 15400 block of 1st Ave. S. at roughly 7 p.m.
The caller said they saw three armed men wearing hoodies enter the shop, according to Cindi West of the King County Sheriff's Office.
Deputies arrived on scene moments later and began trading gunfire with the robbers.
A witness named Chris said he approached the pawn shop during the robbery.
"He was standing with his arms down and I saw him through the window," he said. "He turned and saw me and put the gun to the glass and busted open the door and chased me out with the pistol."
Deputies were able to catch two of the suspected robbers, but at least one is still on the loose.
As the robbery unfolded, three store employees locked themselves in a room inside the store and called police.
"They're obviously pretty scared and frantic, but they're doing well and they're keeping us posted on what's going on," West said.
Police initially weren't sure if any other robbers were inside the shop, so they waited until after 9 p.m. to enter.
When they went in they found the store employees, but didn't find any robbers.
It doesn't appear that anyone was hurt in the incident.
This is just the latest in a recent string of armed pawn shop robberies in the area.
On Jan. 3, police say three masked and armed men robbed a pawn shop located in the 700 block of Martin Luther King Jr. Way South.
On Jan. 24, four men wielding baseball bats and handguns stormed into a White Center pawn shop. The thieves roughed up customers and beat an employee before making off with an unknown amount of jewelry.