Phone tips from the public led police to the Yakima area and Robert "Daniel" Webb, last seen around 5:30 p.m. Wednesday.
Police say 42-year-old Webb of Everett is still at large with his 9-year-old daughter.
The robbery happened around 3 a.m. Tuesday.
The suspect approached the counter, drew out a handgun and demanded money from the register.
The clerk complied and the man and child left without incident.
Clerk Eric Owens said he could see the girl looking confused and frightened.
He said Webb initially spoke in a threatening manner, but he had sad desperation in his eyes.
"His eyes were tearing up. This guy's hurting inside," he said. "He started telling me he worked in a place like this for years. He was fired off his job and his daughter needed medical care."
Owens didn't see which way the suspect went, but police say he was spotted in Yakima around 5:30 p.m. on Tuesday.
Webb is described as 6-foot-2, 245 pounds, brown eye and brown hair.
He was driving a 2008 Silver Toyota Corolla license plate 602-XQG.
"I understand that the man feels that he's in a very desperate situation and right now and our concern is how he is going to deal with this," said Undersheriff Clayton Myers, Kittitas County Sheriff.
Owens says his empathy only goes so far.
"I've been homeless. My son and I have lived on the streets in Seattle. I know what hard is, but resorting to crime is not the solution," he said.