Belton's senseless death has struck a chord nationally and sparked outrage on social media.
"He fought for this country," said Belton's sister, Alberta Tosh, on Friday. "Then he comes home and a couple of creeps kill him in the worst way."
Spokane Police say they have surveillance images of the attackers. Police have released few details about the person they arrested, other than that he is a juvenile male being held on charges of robbery and first degree murder.
Belton was born and raised in Spokane and joined the Army during World War II. Tosh said he was shot in the leg on Okinawa, site of one of the fiercest battles of the war in 1945.
"He was shell-shocked real bad," Tosh, 78, said. "But it got better."
After the war, he spent 33 years working for Kaiser Aluminum, before retiring in 1982.
In retirement, Belton loved to dance, play pool and repair old cars, family members said.
"He was very active and everybody liked him," said niece Pam Hansen. "He'd never think about harming another person."
Belton was called Shorty by his friends because he was little more than 5 feet tall, Hansen said.
She believes he was targeted by the assailants because of his age and size.
"He was defenseless," Hansen said.
A friend, Ted Denison, said he was planning to go to the Eagles Lodge when he heard Belton had died.
"He put his life on the line for our country to come home and 60 years later? Get beat to death?" Denison told The Spokesman-Review. "That's not right."
Denison, a veteran himself, said he used to tease Belton about his membership in the Eagles Lodge, saying that place was for "old fogies." He didn't make it to the lodge in time.
"I don't care who you are, you don't beat up an old man," Denison said. "You're supposed to respect your elders, not beat them to death."
Another close friend, Lill Duncan, said she can't imagine what drove anyone to kill him.
"He lived his life every day to make somebody else happy. It wasn't all about him. It was about what he could do for everybody else."